McDonald’s complaint: Manager wouldn’t help

I just visited a McDonald’s on Cumberland street in Lebanon pa and told them at the drivethru ordering window that i had a coupon on my mobile app for a 12.99 bundle box, the girl didn’t ask for my coupon so i assumed she just gave the discounted price when she handed my receipt i was charged regular price. At the pickup window a manager was handing my food so she said when i asked if she could take my card and recharge for the discounted price she said she cant do that, that she would have to delete the whole payment and re ring it in and she didn’t have the authority to do that. A manager can’t void a payment?? or this manager was too lazy to?? I worked at a McDonald’s for about a year and the manager on duty could definitely do this. The coupon expires today so i just missed out on thisbecause she didn’t feel like it. Why didn’t the girl at the payment window ask me to show the coupon?? Cuz she was too busy talking to her coworkers. Every time I visit this McDonald’s its always something and they are very rude each time someone complains so you have to worry about what you’re eating after you complain. Done coming to McDonald’s after this.