1. You can contact the seller and negotiate a solution. Under normal circumstances, you can ask the seller to compensate for the loss and bear the loss of breach of contract.
2. The system of bona fide acquisition in civil law is not applicable to the owner who buys the mortgaged vehicle knowing that the vehicle is mortgaged, and the vehicle mortgagee has the priority to be compensated and can request the return of the vehicle.
3, can call the police, by the public security organs to investigate and deal with.
Legal basis: Article 394 of the Civil Law of People's Republic of China (PRC) guarantees the performance of debts. If the debtor or a third party mortgages the property to the creditor without transferring the possession of the property, the debtor fails to perform the due debt or the creditor has the right to receive priority compensation for the property.
The debtor or the third party specified in the preceding paragraph is the mortgagor, the creditor is the mortgagee, and the property that provides guarantee is the mortgaged property.