Developer thrusting deficient product n service (apartment)

I'm a customer of a builder-developer. I have been allotted an apartment in mid 2009 which was to be completed n handed over in mid 2013. It hasn't been handed over till date. I've paid about 45 lakhs in instalments against demands raised by developer connected with progress in completion of project. As per contract the final price was 56 lakhs. The developer has violated and continues to violate the following: a) refuses to talk about the reasons for delay, what is left to be done to complete the project, time line for the same, what all regulatory clearances remain to be obtained/complied with, b) refuses to discuss about the contract clause on compensation for delay in delivery which by now has accumulated to be about 7 lakhs. c) refusing to allow n discuss the issue of the apartment confirming to the specifications agreed to in the contract before making further payment. We have learned that developer has failed to obtain regular water n electricity connections and plans to provide the services through generator and tanker which is likely to be exorbitant. Recently the developer has raised a demand note asking me to pay 7 lakhs (last but one) payment by October 7. Friends advise to pay this amount and focus on obtaining possession of the apartment as early as possible. And take up the deficiencies later. Others say this would dilute my case legally for not raising it now. Given the speed and uncertainties of legal system in our country, kindly advise the best course of action.