You have no other options because you need the money.
My friend who wasn't paid at all was told by a lawyer it wasn't worth pursuing.
So much of our legal system, and really society is based off gentlemen agreements. You don't still someone out of 600$ in wages because you don't do that.
When that gentlemen agreement is broken, realistically no lawyer is going to open a case over 600$, you have no real recourse.