Purchased a work Van, but the original owner took it back how can I get my money?

My company purchased a work vehicle from another company who was going out of business a few months back. I had bought it from one of the owners of the former business (the other owner had already parted ways) I made a deposit and 3 payments on this van for over $1600.00 and just this week the former owner (not the one that I purchased from) took the van back because it was in his name and rightfully his. I contacted the person I had bought the van from and they said they couldn't do anything about it. We had an agreement and I've already paid money for this van, how do I get my money back??