diff --git a/.github/workflows/deploy.yaml b/.github/workflows/deploy.yaml
index 0320401..4894b25 100644
--- a/.github/workflows/deploy.yaml
+++ b/.github/workflows/deploy.yaml
@@ -55,4 +55,5 @@ jobs:
           key: ${{ secrets.SSH_PRIVATE_KEY }}
           envs: SECRET_KEY,EMAIL_HOST_PASSWORD,ZIFY_AUTH
           script: |
-            docker compose -f AAISS-2023/docker-compose.yml up -d --pull always --force-recreate --no-build
\ No newline at end of file
+            docker compose -f AAISS-2023/docker-compose.yml pull 
+            docker compose -f AAISS-2023/docker-compose.yml up -d --force-recreate --no-build
\ No newline at end of file
diff --git a/backend/backend_api/models.py b/backend/backend_api/models.py
index e3838f6..37a33e8 100644
--- a/backend/backend_api/models.py
+++ b/backend/backend_api/models.py
@@ -388,7 +388,7 @@ def create_payment_for_user(user: User):
         presentations: list[Presentation] = []
         for workshop in user.registered_workshops.all():
             try:
-                workshop_registration = workshop.workshopregistration_set.get(workshop_id=workshop.id)
+                workshop_registration = workshop.workshopregistration_set.get(workshop_id=workshop.id, user=user)
                 if workshop_registration.status != WorkshopRegistration.StatusChoices.AWAITING_PAYMENT:
                     continue
                 if workshop.remaining_capacity <= 0:
@@ -402,7 +402,7 @@ def create_payment_for_user(user: User):
         for presentation in user.participated_presentations.all():
             try:
                 presentation_participation = presentation.presentationparticipation_set.get(
-                    presentation_id=presentation.id)
+                    presentation_id=presentation.id, user=user)
                 if presentation_participation.status != PresentationParticipation.StatusChoices.AWAITING_PAYMENT:
                     continue
                 if presentation.remaining_capacity <= 0:
diff --git a/backend/backend_api/views.py b/backend/backend_api/views.py
index 1de9006..62df0ed 100644
--- a/backend/backend_api/views.py
+++ b/backend/backend_api/views.py
@@ -216,6 +216,8 @@ class PaymentViewSet(viewsets.GenericViewSet):
     def payment(self, request):
         account = request.user
         call_back = request.data.get('call_back')
+        if call_back is None:
+            return Response(new_detailed_response(status.HTTP_400_BAD_REQUEST, "call_back field is required"))
         try:
             user = User.objects.get(account=account)
         except ObjectDoesNotExist:
@@ -248,7 +250,6 @@ def verify(self, request):
         response = ZIFYRequest().verify_payment(payment.track_id)
         if response['status'] == ZIFY_STATUS_OK:
             payment.update_payment_status(Payment.PaymentStatus.PAYMENT_CONFIRMED)
-            # FIXME: redirect to payment success page
             return Response(new_detailed_response(status.HTTP_200_OK, "Payment verified successfully",  payment.pk))
         else:
             payment.update_payment_status(Payment.PaymentStatus.PAYMENT_REJECTED)