Defy/Builders Warehouse Northgate TERRIBLE customer service!!!!

Bought a R16k oven and ceramic stove, which cracked, due to factory fault....still under 24months warranty. 6 months later, after contacting Defy, their representative who came out and said it must be replaced as was no fault of mine. Spoken to sales people and managers at builders warehouse northgate, where it was purchased. No joy, no replies....just excuses and I still can't cook properly for my family. Have NEVER experienced such terrible after sales service