Bad customer service and ******s

I was overcharged and when I tried to show the supervisor ,she told me how stupid i am and I had to wait there for 45 minutes before they resolved the matter,the supervisor told me she can't give me money if i don't tell her what is it for...she then took me to the manager Lungile who told me that I'm waisting their time then when she realized that they really overcharged me she just threw the money on my face without saying a word