Humiliated by Security Officer

I was just humiliated at Spar Nick's Berea in East London. I did my shopping and went to the till and paid. There was a lady behind me that had a basket with goods in it, I don't know what, she told the cashier something but I wasn't listening to their conversation and then the lady went out the store. The cashier was still to give me my slip. And I asked for it. A few seconds later she asks the security officer if that lady has paid and the officer didn't know and the cashier asked him to please call the lady back. The security either wasn't listening or didn't understand what was said to him but he chased me down. Out the door til by the space they keep their trolleys. He called out to me and asked to see my till slip!!! I told him I wasn't who he's supposed to be chasing and pointed him to the direction the other lady was going, she was still there. I shoved my slip in his hand and left. That was the most humiliating thing that has happened to me, ever. I work across the road from spar, and I was wearing my work uniform as I was on a break. I have a sister that works there. How am I going to show my face there again after that!