An employer fires his employee without paying the pending dues. What to do?

Dear sir/madam,

My boss fired me after 8 months of working for the restaurant and did not pay my last salary for the month of July after he fired me.

He delayed the process of my employment visa untill I got a fine of 3500 AED plus the extra hours of work. He did not pay me for 8 months. I have complained already to the labor many times but my boss keeps promising and lying to the labor that he will pay me.

What should I do?

Do I need to hire a lawyer? I do not have money.

Thanks!