My father bought a car at a dealership and paid in cash. After two years, he then decided to sell the car but realized that he lost the title and the receipt stating that he paid the car in full. SO he went to the DMV to ask for another title. DMV people said that there is a lien on the car and they are not able to give him another title. So he went to the dealership to ask the dealer why there is a lien. The dealer that he talked to was very angry and started shouting making it harder for my father to talk to him and get an explanation. Is this a scam? What should we do to fix this problem?

If he has no proof that he paid in cash for the car, he may be out of luck.

I would try a local consumer advocate's office.