Constant pay changes?

I worked for my employer for 4+ years. In that time he changed my rate of pay multiple times. 10+. He felt he was paying me too much for the job I was performing. He always paid me a base, then a Bonus on top of it. He would always make the Bonus plan to where he felt I could not reach it. When I did reach it, after a couple of months of hitting the bonus, he would change it again and either reduce the Bonus, or reduce the base. Most payday's I would have to spend several hours out of the day explaining what I had done to earn the bonus, and how I did it within the companies guide lines to reach the bonus because if I did not, they would just not pay me for it. It was a weekly battle with them to get them to pay me for what I had done and they came up with multiple excuses as to why they should not pay me correctly. They gave me a written contract in 2008, then changed it multiple times over the next few months, claiming they could because of a clause they wrote into stating they and I have the write to change it at anytime. The contract was not a professional contract, they wrote it off the cuff and was not reviewed by any attorney ever. Finally they stopped giving me a written contract and would just change the way they would pay me at there convince. I always told him how much I needed to live on from day 1, and they agreed to it, but they always tried to make it less for what ever the reason might be. This past year they made the base the lowest it ever was and reduced the bonus to a point where I could not support my family. I was forced to quit to find other suitable employment. I was never written up for poor performance, suspended or reprimanded in any sort of way. When I asked about the most recent change, I was told by the manager, " it's my job to find ways to not pay you and to put money into the company and the owners pocket". That was when I realized it was time to leave the company. Do I have any recourse towards the company?