Execution of sale deed

I have a registered agreement of sale. And have take posession of my flat. The builder is now asking for Rs. 15000 only to get the draft copy inspite of me telling him that the full amount will be paid on the doing of the fair copy, I copy of sale deed issued to another resident estates that the vendor will decide to weather a cooperative society, or any other legal entity will be formed and I shall be binding on the rules and regulation of such entity. This is contrary to that mention on the agreement of sale which estates that the purchaser will form the society. He had converted this complex into a hotel and wants to buy back the premises at 2 lks above cost price after 5 years for completion. He estates in the draft copy that if I want to sell my premises at any given time I will write s letter to him estating my intentions to sell for an X price and be given 14 days time and if they can't match the price that the legal entity will issue a NOC for the same. But no time bar mentioned. He estates I will be binding on all charges decided by such entity which will be formed by him.