New Flat Possession Delay

Hi, Had purchased an under construction flat in Virar - Mumbai around March 2012 and the committed date of possession was Dec 2015. The project was just launched while I booked the flat and builder had sold the flat by an Offer of giving gifts to first 100 purchasers like 1: 1bhk flat, 1: Car, 3: Bikes, 95: 10gm Gold Coin. Also during purchase, i was confirmed that basic internal changes in the flat would be accommodated during construction. None of this expectations are met till date and I am suffering highly due to huge delay in possession. I have been communicating to builder continuously to builder via emails and asked for the possession timely. My visit to the project today showed that the construction is still in-progress and there are so many things pending and possession still might be by Oct 2017. On the other side I found that possession is provided to 2 to 3 owners though the construction is in progress for rest of the building. I am looking this as a willful delay of possession and seeking advice on the reliefs i can seek from the builder against. Looking for a lawyer from Mumbai to help me file a case and seek relief immediately...!! Financial losses Mental stress Rent compensations This being my first house purchase and not investment Failure of achievable dreams of life Many more causing mental / family / financial losses Thanks Nikunj J