Bad service

I'm not happy with the service I got from pick and pay, I bought a cake there and put it inside a trolley and after paying they told me to leave the trolley behind because I only bought one item I can carry it with my hands, I feel they did not treat me like their customer because I bought one item. I cnt carry a cake in mall in my hands I'm not happy they wer so rude to me, I tried to reason with them but I was forced to leave the trolley.