Boitumelo, a rude McDonald's cashier at Karen park crossing.

I am disgusted by the cashier's at the McDonald's wonderpark. The cashier I am talking about is Boitumelo. He told me I cannot change my coke to a fanta. He said it's agaisnt company rules. I asked to see a supervisor or manager but he said they are not in (the time is 8:23) instead he tells me that he's about to get a bonus. I'm very dissatisfied.