我能要回security Deopsit 吗？请老猫帮忙！先谢谢。

The apartment complex I lived in was bought by another company. My lease with the old one was expired in June, 2006. The same time it was bought by the new company. We didn't get a new lease, it was a month to month lease. Then I moved out in Aug. But I didn't get my security deopsit back. I called the new place, the reason was that they asked for a written notice a month ahead of moving. So I wrote a letter arguing that I didn't have a written lease, and I talked to the people work in the company. No one told me the rule. Then I got a letter back saying that I didn't get my security because I moved out before my lease due. It is the New York state law that I am respoisible for the rent. (I know that they sent new lease in Sep. to the people that still live there). I don't want to give up the $1000, is it possible for me to get the money back?