Bad service

I went to express malamulele to do an exchange, I found a store manager without a name badge he said his name is reckon. I told him I lost a slip but the day I bought the trouser I know it because I swiped the card on Tha day. He said something and I didn't hear clearly what he was saying I showed him the slip I have on my phone. He started shouting me and he said he can't assist me and refer me to his assistant. She sent me back to him. He said no I'm not listening to him I explained to him that I didn't get what u want dats y I showed you my slip on my phone. The other cashier asked me where I'm from I told him that I'm venda the manager said Jah dats y. He keeps on shouting me in front of the customers I explained again I didn't get what u where saying. I told him I will report his service, he was busy assisting me on the system he stopped everything and said I must report him. I'm shocked how he became a manager if his behavior is like that. As I'm speaking now I left the trouser and my money with him because he refused to assist me. His service is bad I know I'm wrong by not providing the slip but he showed me that he can assist me even if I don't have a slip. Your feedback regarding this will be highly appreciated.