Purchase of a Hyundai Grandi10--involved in an accident

I purchased a vehicle from Hyundai Ballito and paid cash. At the time of purchase the saleman said that the car was not involved in an accident. Later we took the vehicle to a qualified mechanic who upon checking the car found that it was involved in a front smash and the engine was changed. This vehicle went through a cor test and the 125 point check. The matter was referred to Hyundai Durban who sent the car over to Ballito. Presently I am engaged in a discussion with Hyundai Ballito and am yet to make a decision whether I must request the full refund. Will keep you informed.