No feedback & they don't care

Last year end of September my sister left the rental place which I was renting on her behalf. I had put on a notice on time and I was paying every month with no fail. I sent a lot of e-mails to Marin which most of them were ignored. He has worst service I have ever seen in my life. I called him several times but till today no response nor apology nor deposit of the room for that matter. He said one day when I called finance was responsible but I never dealt with finance before I knew him as a direct contact. Finance knew my money deposits but now that my deposit was due they don't know me. No matter how small the amount but the fact is it is due to me. I want my deposit back.