i bought a used vehicle in april. 3 days after i bought it motor was gone. drove it very little. took it to a mechanic. liquid glass had been poured in the radiator. gave the mechanic a 1000.00. motor for the car would cost 1800-2500. called the place i bought the car. after a month and half, car dealer says, ok come get another car. gave me 500 trade in on car i bought, and i picked up another car. this car is great, now, got a refund for 550.00 from mechanic..check bounced..gave check to car dealer as down payment on new car..now car dealer is trying to repo my car...won't give me the check to go collect the money..called mechanic several times, he keeps saying that he will bring the money...what can i do to keep my car???