Dodgy panel beater in Vryburg

Our Hyundai Veloster was fixed by the said panel beater .The car now blew head because of their shady work.The warranty from the dealer cannot cover as they didn't take the Inn at the Hyundai dealership to be inspected.Have tried calling and ask if for the parts they claim to have changed from a guy called Venon for a week now and he is no longer aswering my call.This shows that they are not competent as they know that cars fixed by any panel beater need to go for inspection after being fixed.Now I don't know what to do as am liable to a R+-30000 bill that I must pay due to them failing to fix the car correct the first time.Please stay away from such panel beaters