Defy gas hob/electric oven

Five years ago I purchased a gas hob/electric oven stove. From the beginning the gas hob had a tiny flame with no heat. I called in the Defy maintenance team - no joy, I called local repairs companies - no joy - they all said it was dirty nipples. I purchased at least 2 gas regulators - I have cursed this stove every day of my life but could not afford to replace it. Last week another maintenance man came to my house for another problem and when asked to check the stove discovered that all the jets on the stove were the wrong size - much too small. It has to be a factory fault. He replaced them with larger nipples and now after 5 years and hundreds of rand spent on call outs I can boil water. The electric oven continues to cook unevenly and often burns my baking. Never, never will I purchase any Defy product.