diff --git a/tests/app/celery/test_ftp_update_tasks.py b/tests/app/celery/test_ftp_update_tasks.py
index 9700c8394..2c6bc4393 100644
--- a/tests/app/celery/test_ftp_update_tasks.py
+++ b/tests/app/celery/test_ftp_update_tasks.py
@@ -23,6 +23,7 @@ from app.celery.tasks import (
 
 from tests.app.db import create_notification, create_service_callback_api
 from tests.conftest import set_config
+from unittest.mock import call
 
 
 def test_update_job_to_sent_to_dvla(sample_letter_template, sample_letter_job):
@@ -114,7 +115,25 @@ def test_update_letter_notifications_statuses_persisted(notify_api, mocker, samp
     assert failed_letter.status == NOTIFICATION_TECHNICAL_FAILURE
     assert failed_letter.billable_units == 2
     assert failed_letter.updated_at
-    assert send_mock.called
+
+    calls = [call([str(failed_letter.id)], queue="notify-internal-tasks"),
+             call([str(sent_letter.id)], queue="notify-internal-tasks")]
+    send_mock.assert_has_calls(calls, any_order=True)
+
+
+def test_update_letter_notifications_does_not_call_send_callback_if_no_db_entry(notify_api, mocker,
+                                                                                sample_letter_template):
+    sent_letter = create_notification(sample_letter_template, reference='ref-foo', status=NOTIFICATION_SENDING,
+                                      billable_units=0)
+    valid_file = '{}|Sent|1|Unsorted\n'.format(sent_letter.reference)
+    mocker.patch('app.celery.tasks.s3.get_s3_file', return_value=valid_file)
+
+    send_mock = mocker.patch(
+        'app.celery.service_callback_tasks.send_delivery_status_to_service.apply_async'
+    )
+
+    update_letter_notifications_statuses(filename='foo.txt')
+    send_mock.assert_not_called()
 
 
 def test_update_letter_notifications_to_sent_to_dvla_updates_based_on_notification_references(
diff --git a/tests/app/notifications/test_notifications_ses_callback.py b/tests/app/notifications/test_notifications_ses_callback.py
index 75e0b16bf..49ce90829 100644
--- a/tests/app/notifications/test_notifications_ses_callback.py
+++ b/tests/app/notifications/test_notifications_ses_callback.py
@@ -50,6 +50,35 @@ def test_ses_callback_should_update_notification_status(
         send_mock.assert_called_once_with([str(notification.id)], queue="notify-internal-tasks")
 
 
+def test_ses_callback_does_not_call_send_delivery_status_if_no_db_entry(
+        client,
+        notify_db,
+        notify_db_session,
+        sample_email_template,
+        mocker):
+    with freeze_time('2001-01-01T12:00:00'):
+
+        send_mock = mocker.patch(
+            'app.celery.service_callback_tasks.send_delivery_status_to_service.apply_async'
+        )
+        notification = create_sample_notification(
+            notify_db,
+            notify_db_session,
+            template=sample_email_template,
+            reference='ref',
+            status='sending',
+            sent_at=datetime.utcnow()
+        )
+
+        assert get_notification_by_id(notification.id).status == 'sending'
+
+        errors = process_ses_response(ses_notification_callback(reference='ref'))
+        assert errors is None
+        assert get_notification_by_id(notification.id).status == 'delivered'
+
+        send_mock.assert_not_called()
+
+
 def test_ses_callback_should_update_multiple_notification_status_sent(
         client,
         notify_db,
diff --git a/tests/app/notifications/test_process_client_response.py b/tests/app/notifications/test_process_client_response.py
index f19909167..40e2a608c 100644
--- a/tests/app/notifications/test_process_client_response.py
+++ b/tests/app/notifications/test_process_client_response.py
@@ -61,10 +61,23 @@ def test_outcome_statistics_called_for_successful_callback(sample_notification,
     success, error = process_sms_client_response(status='3', reference=reference, client_name='MMG')
     assert success == "MMG callback succeeded. reference {} updated".format(str(reference))
     assert error is None
-    assert send_mock.called
+    send_mock.assert_called_once_with([str(sample_notification.id)], queue="notify-internal-tasks")
     stats_mock.assert_called_once_with(sample_notification)
 
 
+def test_sms_resonse_does_not_call_send_callback_if_no_db_entry(sample_notification, mocker):
+    mocker.patch(
+        'app.notifications.process_client_response.notifications_dao.update_notification_status_by_id',
+        return_value=sample_notification
+    )
+    send_mock = mocker.patch(
+        'app.celery.service_callback_tasks.send_delivery_status_to_service.apply_async'
+    )
+    reference = str(uuid.uuid4())
+    process_sms_client_response(status='3', reference=reference, client_name='MMG')
+    send_mock.assert_not_called()
+
+
 def test_process_sms_response_return_success_for_send_sms_code_reference(mocker):
     stats_mock = mocker.patch('app.notifications.process_client_response.create_outcome_notification_statistic_tasks')