It's really not that expensive to send a lawyer threatening letter.
My brother needed a letter sent that threatened legal action concerning a rent problem. It was only a couple hundred in question. He talked to a lawyer, who said that for $40 he sends a certified letter threatening legal action and proposing a solution, knowing full well, that no action would be taken, because for the small sum of money it wasn't worth it. But, it scared the landlord enough and he took care of it.
So for $40, my brother got his $400 back.

good luck,
dragonb