Is refusing overtime allowed?

Upon my hiring I revealed that I required about 20 or so weekends off per year for personal reasons. He said that was fine(without putting it in writing unfortunately) as long as the hours were made up during that week or the next week. It was well known in the shop and worked for 2 years but then he decided to go against his word and force me to work whenever he desired. I refused to work the 1st weekend and when I returned on Monday I was punished by immediately being sent home for 2 days and told the next time I would be fired. I assumed that I would be able to get a new job but almost 3 years and 400 or so applications later I am still stuck there and he is still forcing the weekends. They are paying for the overtime but it is not uncommon to work for months without a day off. I can not quit because because I have financial obligations. Would I be able to collect unemployment if they actually did fire me for refusing to work the weekend?