not giving the possession of the flat .

Location/place: Bangalore

Name of company/service: Srinidhi Residency

We had booked the flat with Srinidhi Residency at Bangalore .We had already paid him the amt. Since last 2 years they are not giving the possession of the flat and not paying back us the amount also.Srinidhi Residency had given us a 2 cheques of PDC . that one of the cheque is also bounced. Please suggest what to do and help us. Mr. Johnson Abraham