Manager who is rude and unprofessional to customers.

Mybuncle bought a silver Urn 6 months ago that has a waranty of 1 year at Jet in Bloemfontein.The Urn is working but it's leaking. I took it back and the lady who claims to be the manager there was rude to me. She refused to give me another Urn (exchange) she even started swearing and talking to me in Afrikaanse even though she could clearly see that I'm black. What is the use of buying a product with 1 year guarantee only to be given grief when you need to exchange. My uncle was not even asking for a refund but an exchange. Can your stuff aslo talk to people properly thaf was unprofessional and very rude. She doesn't even know how to talk to customers. She told my uncle to go back with that Urn and stop bothering her and the stuff. He must just buy an Urn and leave them alone.