diff --git a/app/dao/returned_letters_dao.py b/app/dao/returned_letters_dao.py
index 48e121ce0..7e313178c 100644
--- a/app/dao/returned_letters_dao.py
+++ b/app/dao/returned_letters_dao.py
@@ -8,7 +8,6 @@ from app.dao.dao_utils import transactional
 from app.models import Notification, NotificationHistory, ReturnedLetter
 
 
-
 def _get_notification_ids_for_references(references):
     notification_ids = db.session.query(Notification.id, Notification.service_id).filter(
         Notification.reference.in_(references)
diff --git a/app/models.py b/app/models.py
index a7ece9dbf..577beb64a 100644
--- a/app/models.py
+++ b/app/models.py
@@ -2080,4 +2080,3 @@ class ReturnedLetter(db.Model):
     service_id = db.Column(UUID(as_uuid=True), db.ForeignKey('services.id'), unique=False, index=True, nullable=False)
     service = db.relationship(Service, backref=db.backref('returned_letters'))
     notification_id = db.Column(UUID(as_uuid=True), unique=True, nullable=False)
-
diff --git a/app/service/rest.py b/app/service/rest.py
index e34f90e26..4416a5a39 100644
--- a/app/service/rest.py
+++ b/app/service/rest.py
@@ -942,7 +942,7 @@ def check_if_reply_to_address_already_in_use(service_id, email_address):
         )
 
 
-@service_blueprint.route('/returned-letter-summary')
+@service_blueprint.route('/<uuid:service_id>/returned-letter-summary', methods=['GET'])
 def returned_letter_summary(service_id):
     results = get_returned_letter_summary(service_id)
 
diff --git a/tests/app/db.py b/tests/app/db.py
index 50840bf2c..ac23654c2 100644
--- a/tests/app/db.py
+++ b/tests/app/db.py
@@ -950,11 +950,11 @@ def create_returned_letter(service, reported_at=None):
     template = create_template(service=service, template_type=LETTER_TYPE)
     notification = create_notification(template=template, status=NOTIFICATION_RETURNED_LETTER)
     returned_letter = ReturnedLetter(
-        service_id= service.id,
-        reported_at= reported_at or datetime.utcnow(),
-        notification_id= notification.id
+        service_id=service.id,
+        reported_at=reported_at or datetime.utcnow(),
+        notification_id=notification.id
     )
 
     db.session.add(returned_letter)
     db.session.commit()
-    return returned_letter
\ No newline at end of file
+    return returned_letter
diff --git a/tests/app/service/test_rest.py b/tests/app/service/test_rest.py
index 5677428be..cd6bbae8f 100644
--- a/tests/app/service/test_rest.py
+++ b/tests/app/service/test_rest.py
@@ -47,7 +47,7 @@ from tests.app.db import (
     create_domain,
     create_email_branding,
     create_annual_billing,
-)
+    create_returned_letter)
 from tests.app.db import create_user
 
 
@@ -3372,3 +3372,12 @@ def test_get_monthly_notification_data_by_service(mocker, admin_request):
 
     dao_mock.assert_called_once_with(start_date, end_date)
     assert response == []
+
+
+def test_get_returned_letter_summary(admin_request, sample_service):
+    create_returned_letter(sample_service, reported_at=datetime.utcnow())
+    create_returned_letter(sample_service, reported_at=datetime.utcnow()-timedelta(days=3))
+
+    response = admin_request.get('service.returned_letter_summary', service_id=sample_service.id)
+
+    assert len(response) == 2
\ No newline at end of file