Accused of theft by a rude staff member

I bought a ****gy mat at Mr Price Home in Lifestyle Center however they didn’t have it in white so I settled for the blue color they had. Arrived in Centurion mall and decided to go exchange the mat same day. My slip had been emailed to me and after a long day of shopping, my battery was flat. At the door, I asked one of the ladies what to do if I’m exchanging and she said I must take the replacement item and go to the tills. Upon arriving at the till, your staff member Kholofelo together with her supervisor who saw absolutely nothing wrong with what she was saying, accused me of *****ing the mat from the floor in front of other customers. When I asked her for her name, she refused to give it to me in front of her supervisor Frank and he didn’t intervene at all. I asked her to look through the transactions on my card as I had bought the mat the same day but she continued giving me the worst attitude and treatment I have ever received from any company. It is pathetic for such a big brand to have staff like Kholofelo representing your brand. I will definitely be closing my account and will tell anyone who will listen about this.