How to get back Land sold to housing board and Land Developer

Dear Sir / Madam, My ancestral property (Agriculture land) was sold to Karnataka Housing Board (KHB) as part of land acquisition act, All my family members including myself signed for the sale deed with KHB (Ten years back) Eventually KHB could not acquire surrounding lands in a village and acquisition got cancelled, and KHB succeeded in acquiring only few lands in a village (including our land) and fail to acquire all the Lands in surrounding as per there plan because government cancelled the acquisition. Recently Land Developer approached my family members and convincing them he will get back land from KHB and purchase on behalf of our family members. Except myself all remaining family members signed for an agreement with Land Developer by accepting advance money from him through Cash, DD or Cheque. and later i heard from my family members that Land Developer is not responding for there phone call. During negotiation between me and Land Developer he made a demand draft on my name for some X amount but i declined to sign his agreement and during this time he left his demand draft (prepared on my name) in my house Later i called him through phone and said i am not interested to sell my portion of the Land. And advised his to collect his demand draft left at my home. Please advise what should be my approach / Action to retain my land from KHB and Land Developer 1. Should I return back the demand draft to Land Developer through letter indicating not interested to sell my property ? 2. As i not signed on agreement with Land Developer and also not deposited demand draft provided on my name in my bank account, do i still have any legal bound to Land Developer ? In that case what should be my action to return back the Demand Draft? 3. As my all family members have agreement with Land Developer on stamp paper do they still have authority to file a case on KHB to release back our Land to our family ? 4. How to retain my portion of Land from KHB (Karnataka Housing Board) ? As my family members do not have authority to claim from KHB as they already signed agreement with Land Developer I would appreciate your legal advise and my next action to retain my land and how to dealt with Land Developer