BAD SERVICE!!!!!

I am so upset right now. I came to Pick n Pay Maponya to buy Pastel sheets and when I got to the isle they were R34.99 however at the till it was R42. I told the cashier Nonhlanhla Mkhize that I will pay what they have advertised. She told me to come with her to the isle so she can see for herself...i followed her. She told me that all the different pastel pads have the wrong prices. Now with a very irritated tone , she asked "What do you want me to do"...judging from the tone she used on me, I asked what does she mean and is that how to talk to a customer?! She just lost it...i requested more than 3 times for her to stop shouting at me. I told her shes upsetting me even more and she told me I'm annoying her. I AM SO UPSET!!! We go to white dominant stores and are treated with respect but our fellow Black African people treat us like used toilet paper.