Bad Cashiers Attitude

At Southgate we are told that express cashier doesn't pack the items customer must do it themselves this is always said by one certain cashier though Sibulele others when you there they pack for you. Even the cashiers at Columnbine Square pack at express till. Last time Sibulele did this I asked for manager as she's the only who does this she just ignored me and called the next customer went to the office to ask for manager didn't find any manager there.