You can send a demand letter and possibly get 3x ($750 in your case) if you're willing to take it to small claims court and they're not willing to give it back after the demand letter. There are laws you can find online regarding what fees can be taken as part of the lease and what documents need to be with it.

As others said, it's a small amount and going to court may not be worth it to you or the LL. But sending the demand letter would likely be enough to get them to send it back.