McDonald's Bloemfontein Zastron Rude management

I arrived at McDonald's Bloem Zastron, they put me in the back of the line as it was closing and assured me that my order would be processed, one of the managers came through the window and begun to yell at me for arriving at Closing time and continued to violently tell me how wrong that was, I was purchasing using a coupon from the app which I wasn't able to redeem because the QR code scanner wasn't working, thereafter when I a placed an order for a different special that they had originally said I could have, they suddenly didn't have enough ingredients to make a cheeseburger?? The core product of their business and they didn't have the ingredients, I have now lost the coupon and was not served anything, I didn't receive an apology for anything that happened.