Yup. you are right. I am from Asia. If I refuse the overtime offer, mean that I dont want that job anymore. Actually no overtime paid, just have to finish my work before I can go home. If my boss pay me overtime money, I will be happy to work.
Tell your boss that you won't take shit anymore from him. If he demands you to get back to the rut again, kick his ass and quit. There are enough opportunities if you are smart enough. It's better to earn $1000 and live as you want than to earn $10,000 and live like a slave.
Few years back i was just like you and then I followed cheap seo services advise and see now I am a happy man and I have lots of goats. Do you want to hire them ??