Arrogant, rude, unhelpful dealership selling unroadworthy cars

Really disappointed, heartbroken and disgusted with the Mobeni Hyundai staff. I bought a brand new car from them. Within a week it started troubling. They repaired it. It broke down 4 times. A brand new car does not have engine problems. I was without a car for 3 weeks. The water pipe shot out. Engine overheated. Spark plugs broke on the engine. This car was to give me peace of mind for travelling with a wife and little child. However, it is now a nightmare!!! Worst of all is the Dealer Principal who is the most rude Dealer Principal I have ever met. Arrogant and saying he refuses to help in this matter. Can Head Office intervene. Is there any competent person at Hyundai who can resolve this issue urgently???