Refactor VerifyOTPView to check for existing TemporaryUser and return appropriate error messages

api/views.py

@@ -18,6 +18,7 @@ from api.serializers import (
     OTPVerificationSerializer,
     TemporaryUserSerializer,
 )
+from django.shortcuts import get_object_or_404
 
 # knox imports
 from knox.views import LoginView as KnoxLoginView
@@ -207,11 +208,11 @@ class VerifyOTPView(generics.GenericAPIView):
         serializer.is_valid(raise_exception=True)
         data = request.data
         mobile = data.get("mobile")
+        t_user = get_object_or_404(TemporaryUser, t_mobile=mobile)
+        if not t_user:
+            return Response({"message": "User not found."}, status=404)
 
-        if (
-            User.objects.filter(mobile=mobile).exists()
-            or TemporaryUser.objects.filter(t_mobile=mobile).exists()
-        ):
+        if User.objects.filter(username=t_user.t_username).exists():
             return Response(
                 {"message": "User with this mobile number already registered."},
                 status=400,