You'll only be governed by the builder buyer agreement executed between you and the builder during the time of booking. All other demands, other then the ones agreed upon are arbitrary and should not be paid to him. You can issue legal notice to the builder asking them to explain each and every charges imposed by him without your consent.
If he fails to respond within 15 days of the receipt of the legal notice, you can file a complaint against me in consumer court for deficiency of services and unfair trade practices adopted by him.