Defy appliances sells faulty appliances and refuses to give customers back their money

I bought a brand new defy microwave at ok furniture soweto on the 25th of November and they delivered it on the 26th late so on the 28th when I wanted to use the microwave it was not working I then took it back to the store on the 28th and they said that they have to contact defy for them to either fix it or refund me so the field service manager of defy appliances Thato Fantsi refuses to give me a refund on a broken microwave they had sold to me .