Originally Posted by suzanne4
Call the labor board in the state where they hold their license. If they have a written contract stating that those things were included and do not live up to what they signed, they are 100% libel and the state will take action against them.
One thing a company should not do is not pay wages owed to an employee. The attorney general of that state can actually go after them.
Good luck!

Suzanne is right on.
I hope you got a contract. If not, let that be a hard and unfortunate lesson learned. If you did, definately report them to the labor board of the state you performed the work in. If they are not able to get your money, I would probably not take it any further unfortunately. Retaining a lawyer for such a small amount would probably eat into your $1000 so much as to make it a waste of your time.
Whenever possible it is always best to negotiate a higher hourly rate over a completion bonus in my opinion. In the event your assignment is terminated early for any reason at least you got the "bonus" for the amount of time you worked rather than nothing. A better method for getting "more" is to negotiate the bonus in to your hourly and THEN pre-negotiate a renewal bonus. In the event you renew your contract, you can usually get this by your second or third week of the new contract. It's generally a win-win for both you and the agency.
Edited to add:
Most importantly ALWAYS get EVERYTHING in writing!