Basically, the title says it all. I'm trying to determine if I do fact a valid legal argument.

For some time now, I have lived in a residence which is owned by my employer. The arrangement was mutually beneficial, allowing me to work off rent and saving my employer money by not paying overtime. This arrangement has worked well until recently. My employer is now trying to claim I owe him rent money which I know that I do not in an attempt to exploit free labor from me since his funds are growing tight. I have been feeling somewhat run-down with a cold and the physically demanding work conditions and simply wanted this past Saturday off and I took it. He is now threatening to fire me and kick me out of the house because I refused to work overtime for him. Granted, he is not threatening to fire me for not working overtime, but for just not coming to work.

Now, I'm pretty sure that, legally, I am in the right for being denied overtime pay even though it was a mutual agreement. He has helped me quite a bit in the past and I would feel bad for pursuing legal action but considering the situation, I feel I have been more than reasonable to allow him to deny me overtime for as long as he has when I am only asking for a day of rest.

I'm in my second year of college and simply cannot afford these distractions or I wouldn't even consider pursuing legal action. I would hate to do this to someone who has been good to me in the past, but I cannot allow myself to be exploited when it is convenient.

So, now that you have the story, what would my legal options be?