Fit out possession

I made the hasty decision to take fit out possession from a builder for my under construction flat not knowing the implications. The builder has not got OC and not giving a possession letter. I have made full payment for flat and amenities plus 2 years maintenance in post dated cheques at Rs 9 psf carpet area. Amenities like pool, gym and lift parking are in the agreement but not yet ready. I took fit out possession in February 2016 but the agreement states possession in october 2016. Builder is supplying tanker water but saying that the cost is to be borne by residents. Is this correct or the builder has to bear tanker water charges? Can builder charge for maintenance at full rates including amenities when they are not ready? I agree to pay maintenance but not at the high rates of Rs 9 since no amenities are ready. Can I stop payment of cheques since the contract is not adhered to ie amenities? Also I paid for lift parking but since its not installed park on the road. What are my legal options if builder has not got OC?