Landlord refuses to give any of $700 security deposit back on apartment & will not provide reason; property manager will not give contact information for landlord (Louisiana)

Not sure if I used the semicolon in the title properly, but I'm leaving it. Anyway, last February I moved to New Orleans for a job which needed an in-state address before I could start my job, so I signed a nine month lease on a kinda cheaper, shady apartment. At the end of the lease I went month to month for another three months before moving out.

Before I moved in, I contacted the number on the listing and got in touch with the landlord (read property manager), let's call him Rob, who pulled out a one side front-and-back sheet of paper lease to sign, and I wrote out a personal check with the security deposit and pro-rated first month's rent, made out to Rob. From that point forward however, Rob only accepted cash or cashier's check made out to him for rent.

Through the year I lived there, I had typical low-income housing problems: rats, roaches, broken fridge, broken A/C, no heat, etc. Rob was alright about getting someone to fix most of these things, but not everything, and you usually had to hassle him to get around to returning your call and getting it fixed. One of the issues was a sink where the caulking had deteriorated and the sink started falling off the wall. It still worked fine, but it needed repaired. Rob never got around to fixing this, and I had to just live with it for about 6 months.

So, the lease is up and I get ready to move out, call Rob and tell him I'm leaving and I'm ready for him to take a look through the apartment and give back my deposit. He informs me the landlord will be through in the next few days or week to look around. This caught me a little off guard, since up to this point, Rob had sort of presented himself as the landlord.

Fast forward to approx 6 weeks after I moved out, I call Rob and ask about my security deposit. He replies that the landlord doesn't want to give any of it back. I asked why, he said because of the sink and kinda trailed off saying something about something being dirty (please refer to aforementioned rats, roaches, baby roaches hatching, etc I spent the last year living with). I tell him if I'm not even going to get a partial refund, I need to have an itemized list of deductions from the deposit and some sort of receipts or documentation. Rob tells me he will pass this information along to the landlord, and proceeds to not answer my phone calls or voicemails for the next few weeks. I finally get a hold of him again and tell him I have still not received any of the deposit or deductions. I ask for contact information for the landlord, and he said he couldn't give that information away.

So, that's my problem. Rob is hesitant to answer or return my calls. I can't get in touch with the landlord. I'm out a $700 deposit. I have minimal documentation, just a few pictures and even that doesn't capture much. Not to mention, I don't know all that was supposedly deducted.