I was in a similar position. It’s not really enforceable because if you threaten to take legal action you get fired, and if you stop getting paid you can’t afford lawyer fees, and if you stop working you’re in violation and have to leave the country, and even if you win it’s unclear what you will gain. If you have a family or partner you’re especially in a bind.
I believe you are supposed to register a complaint with the EEOC, after which any adverse actions taken against you including firing without cause could count as illegal retaliation (which isn't the case for just threatening legal action), but I am not a labor attorney (or any sort of lawyer).
USCIS doesn't care about EEOC. And you try fighting your case from abroad. Impossible. No one is going to do it.