Improper behaviour and delay in possession

Dear sir During the year 2011 on the month of April we booked a flat priced at 59 lakhs.The flat was supposed to be handovered to us by the year december 2013 clearly mentioned in the document. Surprisingly when we crossed questioned them about the delay(2.5yrs approx),the concerned person Mr.Daruga from IDEAL BUILDERS misbehaved and thretened us to file a case to court as if we are handicaps to take action against him.Later on,in June 2016 they send us a mail for registration process with any verbal communication.In Oct 2016 the charged an amount of rs 60000 based on 12% rate on 6 lakhs for the period of June 2016 to Oct 2016. Now when we decided to sell it off to a third party(buyer) with an agreed amount of 76 lakhs, where 34.5 was paid during the TripAdvisor agreement and the rest of the amount will be paid during registration process.Now Mr Daruga is putting pressure on us that if are not able to make out by 7th feb 2017 .he may go head with registration without us.