Appalling service from Nontlantla Bewana

I went to purchase an item from your store and requested a cash back from one of your cashiers (her name tag had Bewana Nontlatla). Her facial expression and tone immediately changed when i made this request. Her colleague who i had initially gone to asked her if she would be able to do a cash back on her station for me, prior to me going to her. I went to her till and asked her to give me a sum of R580.00 to which she rudely said she would not be able to give me unless I gave her R20.00. I didn't bother to ask why and opted to increase the amount to R600.00. Throughout the entire time that she was servicing me she was nasty in terms of her facial expression and tone. She then answered an elderly woman who was standing next to me rudely, when she asked if she would be able to assist her with the price of an item which this elderly lady had in her possession. In her response she said she would not be able to assist the lady in a very sarcastic tone and did not give the lady an alternative. I asked her who the store manager was and she responded by pointing to a poster. Clearly this lady does not comprehend customer service and the importance of customers.