Disgusting staff attitude

I just had the most appalling service at Sasol Hill street, while paying at the till my partner went to go get milk and I asked the cashier to be patient while we wait for him.Did your cashier not perform and start screaming unprovoked, this lady even went as far as telling me that me being a means nothing to her. I am so disgusted with the service I received, for a company as big as you, I would expect that your staff attends customer service training