I purchased a 2nd hand car from a dealer and trade in my car to them. it's been near 2 weeks I had collected my new car but my dealer have not de-register the car i traded in and it was not transferred to their company within the 7 days requirement. The dealer did not make full settlement on my previous car bank loan as well till date. After taking over the new car and handed over my car, 11 days later the dealer told me that the car i traded in has some problem with the chassis. What should i do?