Paid builder but he neither giving possession nor money what action

Dear Sir, I had booked a flat with ERA landmarks in Faridabad sector 76, in 2009 and as per the discussions held with the builder the possession had to be offered to us laest by end of 2013 but neither the possession is given to us nor the money is returned to us, they are just giving extended timelines of 6-7 month every time. I have invested more then 20 lacs and feeling helpless. on one side I am paying loan EMI to hdfc bank and on the other side living in rental flat and facing tough time. Kindl guide me. Thanks