Builder demanding money for noc

I have purchased a flat and want to sell the same. Buyer want builder noc for home loan and for that noc, builder is demanding huge amount. Building OC is pending and society is not formed. Also he is not giving any parking area to park vehicles, keeping gates locked meant for vehicle entry. Even after repeated letters regarding OC and parking and lot other issues he is not responding at all. The scheme is under SRA and our wing is saleable. I have copy of plan which I recieved through RTI shows that according to my carpet area one parking is sanctioned. EETC worli doesn't have any record of parking plan. Builder is not giving any detail. Even the architect is not giving any information regarding delay of OC. I am stuck what to do?