Rude staff member(bullying)

There is a woman at the counter that assisted me when I wanted to use my mr price account card she swiped it and let me sign she then said it was not my signature and said I had to put all the stuff I had taken bad I was humiliated as everyone had looked at me as tho I was a ***** I went back the next week and some one else assisted me I paid and was helped with no problems my sister paid after me and the same woman came to the till and asked him if I paid cash or account he told her account she then told him to call me back and check my id and said to him practice makes perfect she is disgusting and something needs to be done I will no longer shop at mr price and will cancel my account if something is not done