Realtymonk - Cheating the owner of the flat

I have rented out my flat in Bangalore to a real estate company named RealtyMonk.com. They are supposed to pay me rent of **,*** per month and they, in turn, can rent it out to *rd party people. They have paid me * months advance of **,***. They have stopped paying me rent since July ****. When enquired they said that there was a merger of two companies and they are solving the financial aspects and will pay the July and Aug rent by end of Aug **** by they did not do so. After which I had given them ** day notice period to handover the flat to me, which ends on the **th of November, ****. They have agreed for the same but they neither paid my dues nor handed over my flat to me. They have leased my flat to a person for * lakh rupees and they are neither paying back * lakh rupees to the tenant to vacate the flat. I have been under tremendous pressure and agony. They do not respond to calls and emails and they ignore the customers. I would like to get my pending dues and also my flat to be handed over to me as soon as possible.