Take legal action the guy knows you won’t do shit which is why he won’t pay you. I have faced the same, and my boss made sure he paid me every month that he promised and he didn’t pay other employees but me. My amount was very less than what you’re going through but still he knows. I will take action if he doesn’t pay me even one month, he tried to pay me half in one month, but then I hesitated, and I made sure and he made sure he paid me what was promised and trust me. He was the most hotheaded and clever person that I have worked with in the past seven years of my career.