Transfer of ownership under pagdi system

Hi.. I am a resident of Mumbai where the house that I stay in is under the pagdi system. I had decided to sell off my room to my neighbor post discussion with the landlord. From the total amount decided for the sale, part amount was paid by the seller to me, the balance amount is still not paid. As the room is under pagdi system, it was necessary for the landlord to consider this deal and also transfer the ownership of the room from me to the seller, which till date has not materialized and even the balance amount that the seller had to pay is not received. We (buyer and seller) mutually decided to cancel this deal as the landlord is not been able to transfer the ownership inspite of repeated reminders and follow ups. The amount that was paid to me initially will be returned to the buyer as per the mutual consent. Is there any law that clarifies wherein if the buyer cancels the deal, the seller needs to pay half the amount and if the seller cancels the deal, then the seller needs to pay double the amount. Apart from a simple receipt of receiving the amount from the buyer, there is no other document that has been signed between me and the buyer. Request to please advise and if there are any other issues that may arise due to this cancellation.