Remedy avaialble for delay in delivery of apartment

We executed Agreement to Sale for purchase of a 3BHK apartment from a builder in Bhubaneswar in November 2015. In the agreement it was mentioned that the Builder will hand over the possession by March 2016 with 3 months grace period. I paid all the payments ( total amounting to around 80%) as per his demand till March 2016. Thereafter he did not raise any demands. However in October 2016, I wrote him to raise the balance demands and handover possession as per schedule. I made the full payment in November 2016 without his demand letter and got the property registered. In December I wrote him to give delivery possession. Now in Feb 2017, he has completed the all work specific to my Flat but the few work in common facilities are pending. Transformer is not charged. Further, he is yet to raise the demand for the parking (1.5 lakh) and service tax(2.1 lakh). The parking has not been registered as a part of Flat as he said the municipal body is not allowing for the same these days. Further he says we have to pay 75000/- in cash for transformer charging. What remedy is available to us for delay. Can we say non receipt of Certificate of completion as on date to be a proof for failure to delivery? I have sent all my letters through e-mail as he does not receive letters is hard copy.