Charging for the wrong thing

I ordered a Double Crunch Meal (Sweet Chili Sauce), and asked how much it was to upsize the chips, too which I was told the total would be R60, when the meal was rung up I was told R67, when I said something I was told that a regular meal is R62.90, so thinking it had gone up drastically in price I paid, I then looked at a colleagues receipt who had paid R55. I went back and was told it was because I ordered a bottle not a cup, which I said nothing about. The balance was refunded, as to not confuse her anymore I decided to just go for regular. When my food was ready I was given the burger without the sauce, and when I complained I was handed a burger that had been sitting for a while already. This is one of many instances where I have encountered numerous mistakes at this branch, ie. Getting a small chips when paying for a large, been given a thing of chips that is half empty, many times been given the wrong order.