Shocking customer service

I have a double oven and both ovens are tripping the electricity. Logged a call with the Defy authorised services centre, Barnard's TV and Appliances Services in Roodepoort. The immediate service was amazing. Seems like this is how they make their money - customers paying the call out fee. Because after this initial interaction this can be rated as the worst service I ever received. After rating them poorly on Google suddenly the technician came out to replace the element. Two elements were brought to be replaced. The one was correctly replaced, the other element was the wrong model. This was for the one oven as they have no idea what to do with the top oven. This company does not return calls. Neither does the owner - as none of my message I left for him has been returned. As for Defy, I logged two call with Defy on their website (5 August and again 16 August) - still waiting for a call or follow up from Defy. In the meantime I have no oven.