Keep that deposit, he made the commitment to you and thats how a court will read it.
If he wants to cry like a beeatch about it tell him to get off you property. If he wont give it up "The cops are on the way" or "Meet ya in court" should set him right.

So long as you have acted in good faith the courts will stand on your side.

2 months, what a c**ksucka. Id be telling him I want more money, not giving it back!!