Appalling service from Pep store Greenstone mall

So I was initially assisted by Winny who gave the the incorrect receipts. I went back to the store to exchange the clothing, however Thandi who was the cashier, that was assisting refused to help me, because according to her I, didn't have a receipt. She further said the receipt I had was only to be kept in the store. I then asked since I had it who then gave it to me. She then kept on asking for my slip. I communicated to her that the slip I gave her is all I have and this was given to me by the lady that assisted me earlier. But she was adamant there was another slip, at one stage I asked how it was possible that I have the store copy, could it be,that it was maybe given to me by error. She then called Sophie who tried to calm the situation but this Thandi kept on talking about me to her as if I was not even there, she was extremely rude and the Sophie couldn't even control her, she also look like a co worker rather than a supervisor or manager poor, poor, poor service.