completion certificate and final registry held up

Dear Sir / Madam, I have purchased a property in Nasik Road area of Nasik (Maharashtra). Building is completed approximately 2 years back. Last year (around Nov '13) builder has submitted an application to Nasik Municipal Corpn (NMC) for building's completion cum occupancy certificate. Till Jan '15th it has not been provided by the NMC. Everytime i ask to the builder, he passes the bug on NMC saying that due to elections in Maharashtra it was not been done, now after election he is saying it is not in my hand. It is 5 floor single tower building project. Initially he got approval for 4 floors only, thereafter he got the copy of approval for the 5th floor also. I have my flat on 1st floor. Initially we refused to stay there before OC and completion cert. but after 6 months when everyone has occupied their flat, I also took the keys from him. He has given physical possession but not ready to give possesion certificate on his letter head. He took all registration fees and court fees in cash from us, now he is delaying which I think that he is deliberately doing. In this condition to avail the OC, Completion and doing the final registration, what should i do? Kindly provide me some solution