A relative of mine is a retired MD state judge. We've talked about rent laws and things like this before. Have they given you an itemized receipt? They are required by law to give you a receipt for the actual costs of any expenses if they are docking your security deposit. If they won't give you a receipt take them to small claims court. Same relative said a lot of times even the threat of suing is enough for them to back down. It's more expensive for this big companies to go to court than to just settle.