mcdonald’s bug

i’m not sure this is the correct subreddit for this question, but i wanted to get some feedback on what has been going on and see if anybody knows how i can go about fixing this problem.

basically every time you go through the mcdonald’s app, you are offered promotions such as 30 percent off a 6 piece nuggets or free fries with the purchase of a drink. once you select one of the promotions, the app gives you a code that you need to provide to the staff member at the drive thru. well the strange part is that every single time i give them my code, their POS system stops working and stays down for quite a while, even after they try restarting it. i have watched them reboot the system myself, and the employees have told me they cannot use it again for some time afterward. because of that, i usually end up getting my food for free, along with everyone else who happened to be in the drive thru when my code was entered. this has happened at every mcdonald’s i have visited, so it does not seem to be an issue with just one location. i have also noticed that i cannot place any delivery orders through the app. every time i try, i get an error message saying, “there was an issue with your payment. please contact a crew member.” it never even attempts to charge my card. the exact same thing happens when i try placing a curbside pickup order. however, if i use the exact same promotion while ordering inside the at a kiosk, everything works normally. does anyone know what i should do or who i should contact about something like this?