Staff incompetence and not paying full attention to customers

Thanks to McDonald's N1 City for a disappointment after driving all the way to them to get breakfast Double burger cheese that I did through the app and because of incompetence, when I got to the window to pay the lady told me that the system doesn't scan the code and all to find out she put the incorrect code, and when she asked again and I was already at the window and I don't understand why she didn't ask while I was still placing an order and the code timed out. The lady after all that asked me what I want to do because now they can't do that order because there is no code, so I told them they must just leave it. I'm so angry wasted my time, my fuel and I was so looking forward to this meal.