Return of a joint security deposit.

Hoping for some input. I recently moved out of an apartment with 3 room mates. My landlord is being difficult, and refuses to return the security deposit, without citing any reasons, just that he will not return it.

None of my roommates want anything to do with a legal suit to get the money back. I was wondering if I have a claim to the entire securit deposit, or just to my portion. I have in writing that they don't want to pursue legal channels, but they do want their security deposit back.

The secutity deposits were submitted individually, but it is a single lease. The landlord has already pointed out that it is one security deposit, submitting rent or a security deposit on an individual basis is just 3-part-payment.

This is, by the way, a New York apartment, but not NYC.