My grandson bought a car from a private party for $700.00. He is 17 years old, but does have a Calif. Driver license. The car is very beat up, the transmission went out on the way home, and I don't think there is any oil in the car. The person he bought it from signed the pink slip and gave it to my grandson. There was no bill of sale though. Is there any way to take this car back or do something legal to get my grandson's money back?