Do I rightfully own this vehicle that I worked for?

Last June, this guy and I made a contract for me to build a fence in payment of a car he has. In the contract, there are no dates saying when it had to be done, or how long of a fence it has to be. Anyway, I got most of the fence built but being a nice guy, I helped him with other things around his farm and ran out of summer time so I couldn't get part of the fence done that was across the river due to flooding. So one day, he called me and told me I had to bring the car back before 9 or he would call the cops and tell them I stole it. I was using the car for transportation to get to his house. Me not wanting to get into trouble, I took it back, and since he was really intoxicated I thought he will give me a call in a few days and explain why he did what he did but no. He never paid me for the work that has been put towards the car and he still has the car. I've called his house, no answer, I've written him letters and put them in the mail box, still no response. So in other words I just want to know what else I can do to get the car back because I feel that I have already paid for it.