Disgusted at the service

I went to shoprite at Kagiso mall this morning to buy some food. As usual, one gets to the till and greets the cashier, You know, RESPECT! I greeted the lady and she did not respond. She spoke to the security guard and continued fiddling with her till as though I was not there. I waited for her to finish whatever it was that she was doing, and at this point I am actually waiting for her to greet and smile. She looked at me and took the food I had in my hand, then proceeded to scan all my staff. I was shocked when I told her that I greeted her and she didn't bother to say sorry, she just said, I DIDN'T HEAR U, with the most disgusting attitude. I work in a service industry, and I do not take lightly to getting bad service. This lady is soo rude. She then made a comment that she is angry that someone is at the Kiosk and is not working, like that is any of my business...I am so angry at the way this lady treated me as a customer.