Refactor UpdatePaymentSerializer to include only number_of_months field, add DeletePaymentView for payment deletion, and enhance VerifyPaymentView with payment_id lookup. Introduce pending_payment_id field in DeviceSerializer to track unpaid payments.

billing/urls.py

@@ -5,6 +5,7 @@ from .views import (
     VerifyPaymentView,
     PaymentDetailAPIView,
     UpdatePaymentAPIView,
+    DeletePaymentView,
 )
 
 urlpatterns = [
@@ -15,5 +16,12 @@ urlpatterns = [
         UpdatePaymentAPIView.as_view(),
         name="update-payment",
     ),
-    path("verify-payment/", VerifyPaymentView.as_view(), name="verify-payment"),
+    path(
+        "payment/<str:pk>/delete/",
+        DeletePaymentView.as_view(),
+        name="delete-payment",
+    ),
+    path(
+        "payment/<str:pk>/verify/", VerifyPaymentView.as_view(), name="verify-payment"
+    ),
 ]