handle the response in the controller

app/controllers/discourse_donations/charges_controller.rb

@@ -14,6 +14,7 @@ module DiscourseDonations
       else
         payment = DiscourseDonations::Stripe.new(secret_key, stripe_options)
         response = payment.charge(email, params)
+        response['message'] = response['outcome']['seller_message']
       end
 
       response['rewards'] = []

app/services/discourse_donations/stripe.rb

@@ -20,7 +20,6 @@ module DiscourseDonations
         description: description,
         currency: currency
       )
-      @charge[:message] = @charge[:outcome][:seller_message] if @charge[:outcome]
       @charge
     end