What can i do to get the police to help out?

If you told them that story and they won't get a warrant then its becasue they feel his statement is not enough to support probable cause. I would contact the man and offer him money to get the vehicle back. But notify the police and when he show up with the item they can charge him for receiving stolen property. You will get your vehicle back and not have to pay him. If you feel that he wasn't the one who stole it and you tricked him you can always drop the charge.