Poor service

I received the worst service from a guy named Khumbudzo who identified himself as the store manager there. I bought two dresses amounting to R240 from a store in Cresta, unfortunately I lost the slip and went to the Alex branch to exchange. Khumbudzo refused to listen to me, he was very rude and refused to exchange for me. I asked him to check with Cresta for the record and he refused. I then called Head office using my phone in store, spoke to Mandisa who told him to exchange. Still he refused. I am really disappointed with the way this guy undermined me and his manner of approach. He lacks professionalism and not customer centric.