Kelvinator not up to scratch!

I bought a big 6 gas hub and electric Kelvinator oven. Within its 2 year guarantee, the electronics inside burned out and the oven didn't heat up. They came to fix it. 2 months after the guarantee expired, the same thing happened again. Mr Steve Maimela came to fix it and charged me R850. 2 months after this, the SAME thing happened again. Steve promised to come the next day - he never showed. I phoned Kelvinator head quarters and Mr Khumbuzo assured me that a technician will contact me in 24 hours. It is now 4 days later and still no one showed!! Getting very aggravated!