Before proceeding as per experts advice, get copies of documents executed and HP Agreement executed by the bank and whether you have received such notices asking you to repay the money and that they will be constrained to take possession of the vehicle.
According to my knowledge, the agreement states that the owner is Bank and the vehicle is only hired to the owner and the financier is having such powers to take possession of the vehicle and the borrower must have executed such document.
Without adequate powers, Bank can never resort to such illegal things risking their career and personal safety. Unless the mutual agreements are studied by experts do not conclude on your own.