Agency owes me money

In October, I did a modeling job in NY, a job which I acquired through an agency. I have a voucher from this work. I was supposed to have received my payment ($2,000 minus the 20% agency fee, so $1,600) within 90 days. Never received it, and it's been way over 90 days. When I spoke to the agency last week, they said there had been some glitch with the advertising agency that the job was for, and that they would take care of it and make sure I was paid as soon as possible.

Today I received an e-mail from an agent who was quitting the agency, saying that the agency hasn't paid any of their models for months and that she sincerely hoped that we would all be paid soon. It didn't sound promising. Now I'm concerned that the agency will be going under and I'll never get paid for the job.

How would you suggest I proceed with this matter, if I wind up not getting paid soon?