Supervisor Refusal Of Service

My mother couldn't manage to walk through the shop and decided to use a trolley for stability. We've had a total of 10 items in the trolley and the cashier at the express till (THULI, SUPERVISOR) refused us service, Stating that we have a trolley and she cannot go against the company policy. We went into another queue and the cashier gladly served us (Mbali). About a minute later, Thuli cashed up. Pathetic service from Thuli and she should be reprimanded. As a supervisor, this is not the behavior you expect.