Owner not returning security deposit.

I have the following situation and looking to see what are my options: I was renting a place in Domlur 5th Main for almost a year and moved out of the builder floor after giving 2 months’ notice. The landlord stays in Yeshwantpur and he informed me that he will settle the amount of 15k of the deposit that I paid him within a week. Since I had already booked another place I had to leave and returned the key since he insisted that he had to show the place to others to rent. It’s been 3 months now and he hasn’t returned my money. I visited the place last week and I get to know from tenants living there that the same case has happened to a few who left from there and had visited the building in case the owner comes by. They own around 8 buildings in Bangalore and is also working as an engineer in TCS but the owner keeps neglecting my calls and isn’t responding. There is a new tenant who has already occupied the building. I do hear there are legal procedures but I have read that owner usually files for damage. Appreciate any suggestions as how to handle this. Also beware those who are looking to rent a place there.