Why humiliate infront of other customers?

Why humiliate infront of other customers. Cashier calls next I step up to her she decides to give collections whilst I wait infront of her. Then when she's done she tells me to go back to the queue as I head back she calls the guy who was behind me and assists him, now I'm confused, then I go the next available cashier I ask why is their colleague acting strange towards me, well the least they could was apologize for her l, which I'm greatful for. When she calls my order number 291 I go to collect hand over my slip but she calls other numbers 295, customer from behind comes to collect and I'm standing there like a fool am I suppose to beg for her attention. The lady asked me why is she treating me like this, I was puzzled. Another reason I don't like buying Romans Pizza from Sonpark.