Cheated by Arun Dev Builder

Dear Sir I had purchased a 100 sq yard plot from Arun Dev Builder at Dev City Bhiwadi in 2007.As per scheme,rate per sq yard was Rs 3191/-.Rs 1 lac advance and balance 2,19,000/- in 73 equalised instalment s of RS 3,000/- pm.I paid RS 2,56,000/- but till date I have not been given possession of any land.I have not received any letter from their side.Their office is in Chitranjan park Delhi.In Jan,2017,tried to take legal help.As per instructions of lawyer,I sent 2 letters to their address,one through registered post and other through courier.Unfortunately both letters were returned saying Arun Dev builder not available at that address,though all officials of Arun Dev available at this address all working days.My lawyers told me that they can not do anything till letters are received.What type of Constitution exists in our country?.A builder has looted us and we can not do anything against him.I think this is the right time to change this helpless Constitution.Can our Prime minister Modi ji help us in this matter?