Poor Customer Service

Today (02 June 2022) I went to activate the revolving credit given at IC Rosebank, the cashier was not friendly at all and I went ahead to purchase an item worth R300, when I asked for my installment, she tells me her system shows R410 and asked her how so coz the item is only R300, she rudely told me that is what is shown on her system and told me to call their customer care and helped another lady behind as if I was done. on the till slip it shows Dorris Chauke and not sure if that's her name. Why must I call the customer care with my own airtime yet the fault is on her system? Is that service I should be expecting? You might as well keep your business if that is the case, a simple courtesy and excellent customer service goes a long way.