diff --git a/app/main/views/platform_admin.py b/app/main/views/platform_admin.py
index 50917c819..eb7eb7647 100644
--- a/app/main/views/platform_admin.py
+++ b/app/main/views/platform_admin.py
@@ -368,6 +368,9 @@ def platform_admin_returned_letters():
 
         try:
             letter_jobs_client.submit_returned_letters(references)
+            redis_client.delete_cache_keys_by_pattern(
+                'service-????????-????-????-????-????????????-returned-letters-statistics'
+            )
             redis_client.delete_cache_keys_by_pattern(
                 'service-????????-????-????-????-????????????-returned-letters-summary'
             )
diff --git a/app/models/service.py b/app/models/service.py
index 20c841c33..c053438cc 100644
--- a/app/models/service.py
+++ b/app/models/service.py
@@ -1,8 +1,4 @@
-from datetime import datetime, timedelta
-
-from dateutil.parser import parse
 from flask import abort, current_app
-from notifications_utils.timezones import local_timezone
 from werkzeug.utils import cached_property
 
 from app.models import JSONModel
@@ -668,30 +664,25 @@ class Service(JSONModel):
             if test:
                 yield BASE + '_incomplete' + tag
 
+    @cached_property
+    def returned_letter_statistics(self):
+        return service_api_client.get_returned_letter_statistics(self.id)
+
     @cached_property
     def returned_letter_summary(self):
         return service_api_client.get_returned_letter_summary(self.id)
 
     @property
-    def most_recent_returned_letter_report(self):
-        if not self.returned_letter_summary:
-            return None
-        return parse(
-            self.returned_letter_summary[0]['reported_at'] + " 00:00:00"
-        ).replace(tzinfo=local_timezone)
+    def count_of_returned_letters_in_last_7_days(self):
+        return self.returned_letter_statistics['returned_letter_count']
 
     @property
-    def count_of_returned_letters_in_last_7_days(self):
-        seven_days_ago = (
-            datetime.now() - timedelta(days=7)
-        ).replace(
-            hour=0, minute=0, second=0
-        )
-        return sum(
-            report['returned_letter_count']
-            for report in self.returned_letter_summary
-            if parse(report['reported_at'] + " 00:00:00") >= seven_days_ago
-        )
+    def date_of_most_recent_returned_letter_report(self):
+        return self.returned_letter_statistics['most_recent_report']
+
+    @property
+    def has_returned_letters(self):
+        return bool(self.date_of_most_recent_returned_letter_report)
 
     @property
     def contact_lists(self):
diff --git a/app/notify_client/service_api_client.py b/app/notify_client/service_api_client.py
index b89e5c196..b0ad13904 100644
--- a/app/notify_client/service_api_client.py
+++ b/app/notify_client/service_api_client.py
@@ -569,6 +569,10 @@ class ServiceAPIClient(NotifyAdminAPIClient):
     def get_service_data_retention(self, service_id):
         return self.get("/service/{}/data-retention".format(service_id))
 
+    @cache.set('service-{service_id}-returned-letters-statistics')
+    def get_returned_letter_statistics(self, service_id):
+        return self.get("service/{}/returned-letter-statistics".format(service_id))
+
     @cache.set('service-{service_id}-returned-letters-summary')
     def get_returned_letter_summary(self, service_id):
         return self.get("service/{}/returned-letter-summary".format(service_id))
diff --git a/app/templates/views/dashboard/_inbox.html b/app/templates/views/dashboard/_inbox.html
index a73ee296c..901b23195 100644
--- a/app/templates/views/dashboard/_inbox.html
+++ b/app/templates/views/dashboard/_inbox.html
@@ -17,7 +17,7 @@
       {% endif %}
     </a>
   {% endif %}
-  {% if current_service.returned_letter_summary %}
+  {% if current_service.has_returned_letters %}
     <a id="total-returned-letters" class="govuk-link govuk-link--no-visited-state banner-dashboard" href="{{ url_for('main.returned_letter_summary', service_id=current_service.id) }}">
       <span class="banner-dashboard-count">
         {{ current_service.count_of_returned_letters_in_last_7_days|format_thousands }}
@@ -26,7 +26,7 @@
         returned {{ message_count_label(current_service.count_of_returned_letters_in_last_7_days, 'letter', suffix='') }}
       </span>
       <span class="banner-dashboard-meta">
-        latest report {{ current_service.most_recent_returned_letter_report|format_delta_days }}
+        latest report {{ current_service.date_of_most_recent_returned_letter_report|format_delta_days }}
       </span>
     </a>
   {% endif %}
diff --git a/tests/app/main/views/test_accept_invite.py b/tests/app/main/views/test_accept_invite.py
index c5631ce2a..45ab72622 100644
--- a/tests/app/main/views/test_accept_invite.py
+++ b/tests/app/main/views/test_accept_invite.py
@@ -149,7 +149,7 @@ def test_accepting_invite_removes_invite_from_session(
     mock_get_billable_units,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     fake_uuid,
     user,
     landing_page_title,
@@ -477,7 +477,7 @@ def test_new_invited_user_verifies_and_added_to_service(
     mock_get_service_statistics,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     mock_create_event,
     mocker,
 ):
diff --git a/tests/app/main/views/test_dashboard.py b/tests/app/main/views/test_dashboard.py
index 208cd1e20..34d29dbd7 100644
--- a/tests/app/main/views/test_dashboard.py
+++ b/tests/app/main/views/test_dashboard.py
@@ -143,7 +143,7 @@ def test_get_started(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     mocker.patch(
         'app.template_statistics_client.get_template_statistics_for_service',
@@ -168,7 +168,7 @@ def test_get_started_is_hidden_once_templates_exist(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     mocker.patch(
         'app.template_statistics_client.get_template_statistics_for_service',
@@ -194,7 +194,7 @@ def test_inbound_messages_not_visible_to_service_without_permissions(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
 
     service_one['permissions'] = []
@@ -219,7 +219,7 @@ def test_inbound_messages_shows_count_of_messages_when_there_are_messages(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     service_one['permissions'] = ['inbound_sms']
     page = client_request.get(
@@ -246,7 +246,7 @@ def test_inbound_messages_shows_count_of_messages_when_there_are_no_messages(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary_with_no_messages,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     service_one['permissions'] = ['inbound_sms']
     page = client_request.get(
@@ -488,7 +488,7 @@ def test_returned_letters_not_visible_if_service_has_no_returned_letters(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     page = client_request.get(
         'main.service_dashboard',
@@ -511,21 +511,11 @@ def test_returned_letters_shows_count_of_recently_returned_letters(
     mock_get_inbound_sms_summary,
 ):
     mocker.patch(
-        'app.service_api_client.get_returned_letter_summary',
-        return_value=[
-            # Today (should be counted)
-            {
-                'returned_letter_count': 1000, 'reported_at': '2020-01-10'
-            },
-            # Just within the last 7 days (should be counted)
-            {
-                'returned_letter_count': 3000, 'reported_at': '2020-01-3'
-            },
-            # Just after the last 7 days (should not be counted)
-            {
-                'returned_letter_count': 2000, 'reported_at': '2020-01-2'
-            },
-        ],
+        'app.service_api_client.get_returned_letter_statistics',
+        return_value={
+            'returned_letter_count': 4000,
+            'most_recent_report': '2020-01-10',
+        },
     )
     page = client_request.get(
         'main.service_dashboard',
@@ -540,29 +530,29 @@ def test_returned_letters_shows_count_of_recently_returned_letters(
     )
 
 
-@pytest.mark.parametrize('reporting_date, expected_message', (
-    ('2020-02-02', (
+@pytest.mark.parametrize('reporting_date, count, expected_message', (
+    ('2020-02-02', 1, (
         '1 returned letter latest report today'
     )),
-    ('2020-02-01', (
+    ('2020-02-01', 1, (
         '1 returned letter latest report yesterday'
     )),
-    ('2020-01-31', (
+    ('2020-01-31', 1, (
         '1 returned letter latest report 2 days ago'
     )),
-    ('2020-01-26', (
+    ('2020-01-26', 1, (
         '1 returned letter latest report 7 days ago'
     )),
-    ('2020-01-25', (
+    ('2020-01-25', 0, (
         '0 returned letters latest report 8 days ago'
     )),
-    ('2020-01-01', (
+    ('2020-01-01', 0, (
         '0 returned letters latest report 1 month ago'
     )),
-    ('2019-09-09', (
+    ('2019-09-09', 0, (
         '0 returned letters latest report 4 months ago'
     )),
-    ('2010-10-10', (
+    ('2010-10-10', 0, (
         '0 returned letters latest report 9 years ago'
     )),
 ))
@@ -579,15 +569,15 @@ def test_returned_letters_only_counts_recently_returned_letters(
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary_with_no_messages,
     reporting_date,
+    count,
     expected_message,
 ):
     mocker.patch(
-        'app.service_api_client.get_returned_letter_summary',
-        return_value=[
-            {
-                'returned_letter_count': 1, 'reported_at': reporting_date
-            },
-        ],
+        'app.service_api_client.get_returned_letter_statistics',
+        return_value={
+            'returned_letter_count': count,
+            'most_recent_report': reporting_date,
+        },
     )
     page = client_request.get(
         'main.service_dashboard',
@@ -609,7 +599,7 @@ def test_should_show_recent_templates_on_dashboard(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     mock_template_stats = mocker.patch('app.template_statistics_client.get_template_statistics_for_service',
                                        return_value=copy.deepcopy(stub_template_stats))
@@ -663,7 +653,7 @@ def test_should_not_show_recent_templates_on_dashboard_if_only_one_template_used
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     stats,
 ):
     mock_template_stats = mocker.patch(
@@ -818,7 +808,7 @@ def test_should_show_upcoming_jobs_on_dashboard(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     page = client_request.get(
         'main.service_dashboard',
@@ -875,7 +865,7 @@ def test_correct_font_size_for_big_numbers(
     mock_get_jobs,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     service_one,
     permissions,
     totals,
@@ -912,7 +902,7 @@ def test_should_not_show_jobs_on_dashboard_for_users_with_uploads_page(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     page = client_request.get(
         'main.service_dashboard',
@@ -1107,7 +1097,7 @@ def test_menu_send_messages(
     mock_get_usage,
     mock_get_inbound_sms_summary,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     service_one['permissions'] = ['email', 'sms', 'letter', 'upload_letters']
 
@@ -1143,7 +1133,7 @@ def test_menu_send_messages_when_service_does_not_have_upload_letters_permission
     mock_get_usage,
     mock_get_inbound_sms_summary,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     with app_.test_request_context():
         resp = _test_dashboard_menu(
@@ -1168,7 +1158,7 @@ def test_menu_manage_service(
     mock_get_service_statistics,
     mock_get_usage,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     mock_get_free_sms_fragment_limit,
 ):
     with app_.test_request_context():
@@ -1200,7 +1190,7 @@ def test_menu_manage_api_keys(
     mock_get_service_statistics,
     mock_get_usage,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     mock_get_free_sms_fragment_limit,
 ):
     with app_.test_request_context():
@@ -1230,7 +1220,7 @@ def test_menu_all_services_for_platform_admin_user(
     mock_get_service_statistics,
     mock_get_usage,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     mock_get_free_sms_fragment_limit,
 ):
     with app_.test_request_context():
@@ -1263,7 +1253,7 @@ def test_route_for_service_permissions(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     with app_.test_request_context():
         validate_route_permission(
@@ -1317,7 +1307,7 @@ def test_service_dashboard_updates_gets_dashboard_totals(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     mocker.patch('app.main.views.dashboard.get_dashboard_totals', return_value={
         'email': {'requested': 123, 'delivered': 0, 'failed': 0},
@@ -1500,7 +1490,7 @@ def test_org_breadcrumbs_do_not_show_if_service_has_no_org(
     mock_get_jobs,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     page = client_request.get('main.service_dashboard', service_id=SERVICE_ONE_ID)
 
@@ -1515,7 +1505,7 @@ def test_org_breadcrumbs_do_not_show_if_user_is_not_an_org_member(
     active_caseworking_user,
     client_request,
     mock_get_template_folders,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
 ):
     # active_caseworking_user is not an org member
 
@@ -1538,7 +1528,7 @@ def test_org_breadcrumbs_show_if_user_is_a_member_of_the_services_org(
     mock_get_jobs,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     active_user_with_permissions,
     client_request,
 ):
@@ -1566,7 +1556,7 @@ def test_org_breadcrumbs_do_not_show_if_user_is_a_member_of_the_services_org_but
     mock_get_jobs,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     active_user_with_permissions,
     client_request,
 ):
@@ -1591,7 +1581,7 @@ def test_org_breadcrumbs_show_if_user_is_platform_admin(
     mock_get_jobs,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     platform_admin_user,
     platform_admin_client,
 ):
@@ -1623,7 +1613,7 @@ def test_should_show_usage_on_dashboard(
     mock_get_jobs,
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters,
     permissions,
 ):
     service_one['permissions'] = permissions
diff --git a/tests/app/main/views/test_platform_admin.py b/tests/app/main/views/test_platform_admin.py
index a157e3e46..84ce28a63 100644
--- a/tests/app/main/views/test_platform_admin.py
+++ b/tests/app/main/views/test_platform_admin.py
@@ -706,9 +706,10 @@ def test_platform_admin_submit_returned_letters(mocker, platform_admin_client):
     )
 
     mock_client.assert_called_once_with(['REF1', 'REF2'])
-    redis.delete_cache_keys_by_pattern.assert_called_once_with(
-        'service-????????-????-????-????-????????????-returned-letters-summary'
-    )
+    assert redis.delete_cache_keys_by_pattern.call_args_list == [
+        call('service-????????-????-????-????-????????????-returned-letters-statistics'),
+        call('service-????????-????-????-????-????????????-returned-letters-summary'),
+    ]
     assert response.status_code == 302
     assert response.location == url_for('main.platform_admin_returned_letters', _external=True)
 
diff --git a/tests/app/main/views/test_sign_out.py b/tests/app/main/views/test_sign_out.py
index 2d1be4c2f..fdb604acf 100644
--- a/tests/app/main/views/test_sign_out.py
+++ b/tests/app/main/views/test_sign_out.py
@@ -31,7 +31,7 @@ def test_sign_out_user(
     mock_get_usage,
     mock_get_free_sms_fragment_limit,
     mock_get_inbound_sms_summary,
-    mock_get_returned_letter_summary_with_no_returned_letters,
+    mock_get_returned_letter_statistics_with_no_returned_letters
 ):
     with client_request.session_transaction() as session:
         assert session.get('user_id') is not None
diff --git a/tests/app/notify_client/test_service_api_client.py b/tests/app/notify_client/test_service_api_client.py
index de7e731be..ef8dfc33d 100644
--- a/tests/app/notify_client/test_service_api_client.py
+++ b/tests/app/notify_client/test_service_api_client.py
@@ -335,6 +335,25 @@ def test_client_returns_count_of_service_templates(
             ],
             {'data_from': 'api'},
         ),
+        (
+            service_api_client.get_returned_letter_statistics,
+            [SERVICE_ONE_ID],
+            [
+                call('service-{}-returned-letters-statistics'.format(SERVICE_ONE_ID))
+            ],
+            None,
+            [
+                call('service/{}/returned-letter-statistics'.format(SERVICE_ONE_ID))
+            ],
+            [
+                call(
+                    'service-{}-returned-letters-statistics'.format(SERVICE_ONE_ID),
+                    '{"data_from": "api"}',
+                    ex=604800,
+                )
+            ],
+            {'data_from': 'api'},
+        ),
     ]
 )
 def test_returns_value_from_cache(
diff --git a/tests/conftest.py b/tests/conftest.py
index 1510ccf1f..fa31dc42f 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -3496,6 +3496,17 @@ def mock_template_preview(mocker):
     mocker.patch('app.template_previews.TemplatePreview.from_utils_template', return_value=example_response)
 
 
+@pytest.fixture(scope='function')
+def mock_get_returned_letter_statistics_with_no_returned_letters(mocker):
+    return mocker.patch(
+        'app.service_api_client.get_returned_letter_statistics',
+        return_value={
+            'returned_letter_count': 0,
+            'most_recent_report': None,
+        },
+    )
+
+
 def create_api_user_active(with_unique_id=False):
     return {
         'id': str(uuid4()) if with_unique_id else sample_uuid(),