Handle invalid VAT number case

datacenterlight/views.py

@@ -547,6 +547,16 @@ class PaymentOrderView(FormView):
                 vat_number=address_form.cleaned_data.get('vat_number')
             )
 
+            if 'response_object' in validate_result:
+                address_form.add_error(
+                    "__all__", validate_result["error"]
+                )
+                return self.render_to_response(
+                    self.get_context_data(
+                        billing_address_form=address_form
+                    )
+                )
+
             request.session["vat_validation_status"] = validate_result["status"]
             request.session["vat_validated_on"] = validate_result["validated_on"]