Unhappy client

Had a laybuy receipt on hand and was trying to make a conversation with the cashier when she asked me to step aside so she can help clients behind me, I then told her that she needs to assist me first by scanning the receipt as I was not sure if that's an outstanding laybuy. We had an unnecessary argument. She then let me stand aside for more than 15minutes for someone to come fetch my slip in order for the items to be fetched from the back. I had to find out again when will I be assisted, she then asked a colleague to get the stuff. I had few items I needed changed and was being pushed from pillar to post before I could be assisted. Her Supervisor cashed her till up while I was standing next to them for assistance, she referred me to the next till whereby the guy assisted someone who came after me. The third cashier was not willing to do an exchange and assisted another client. Not only was my time wasted, the lack of professionalism. The entire stuff needs training on customer service 01/04/2021