These guys are scum for letting you work blindly without 1) having any idea how or when they would pay what they committed to and 2) warning you they're circling the drain. They deserve to get nailed for it.

That said, it doesn't sound like you have a long employment history, so a cordial relationship and good references from them might be worth more than the money they're unlikely ever to be able to pay, no matter how you go after them. Consider hanging tight at least until you risk losing the right to claim your due (I have no idea if there's anything like a statute of limitations on wage claims or suits).

Good luck. I've been through "oops, we're about out of money, guys", but I was fortunate they were honest and ethical about it.