Inattentive supervisor

I was shopping at the store about 4pm today. The cashier had rung an item which I wanted to voided. The supervisor savy had come to attend to the problem on hand. The supervisor was amused at something as she was giggling and laughing. When I had paid for my items I noticed that the item in question was not voided. I went back to the cashier to point out the error. Savy was adamant that she had not attended to the problem. How can pick n pay employ supervisors that deny their fault and absolve themselves from the problem. Thank God that the supervisor velile had taken control and rectified the issue whilst apologizing. Velile needs to b given recognition for being compassionate