Rude cashiers at Mac Donald's

Disgusting service I received from Mc Donald's in Rosebank Mall (The Zone) today. Walked to buy ice cream and one of their ladies by the door gave me a discount coupon and I was excited Abt it but when I got to the cashier to buy it she seemed irritated and rudely told me she doesn't have change for the R100 I gave her to buy 3 ice creams and said I must stand aside, the manager was there as well, she also collaborated that they don't have change which was surprising- giving attitude and seemed irritated by the discount coupons I guess.. Being polite I stood there but still that wasn't enough, out of nowhere one of their waitresses comes with a tray full of cold drinks about 4 of them, she pushes her tray towards me trying to get me to move away since I seemed to irritate then by wanting to use coupons to buy, leading to all those cold drinks falling off the tray and spilling on my phone which I had put on top of the counter plus all that cold drink spilled on me...the manager who was there seeing everything unfold never said any word but continued with her wor****! How ****ed up can that be that managers give customers attitude and cannot even reprimand their staff? Is having a coupon in Mac Donald a sinful thing? If so then why give customers?? I'm so ****ed off cos I never got any apology whatsoever instead people carried on like nothing happened and I'm not surprised if the manager is the one giving customers then obviously the whole staff will do the same