Horrible customer service ever

I was shopping with my wife today at our local shoprite in kanyamazane store I was holding our 1 month infant we walked to the cashier she told us to use the next 1 as she was closed. To my surprise she allowed a colleague to pay,after that she allowed another customer to pay I asked her why did she do such thing she told me this customer had left a magazine on the counter.I said but this is not fair she told me the was nothing she could do. I asked in a calm manner for the supervisor she bluntly told me she doesn't know where the supervisor is. if I wanted her/him I must find them on my own until a till packer came and asked what was the problem I explained to her I wanted to speak to a supervisor which eventually came to my rescue. I explained to her the situation which the cashier was still arguing with me about the scenario.the cashier BONGEKILE NKOSI was told not to argue with me but she persisted. Up until i eventually left the store. I'm a sales consultant I work with clients I know what is expected of customer service.because I was wearing rags it gives her the right to treat me the way she did. I wonder what kind of people shoprite employes