If the vendor refuses to perform his part of the agreement to sell(contract) then get issued a notice through a lawyer, providing the date and time when the vendee will appear in the sub-registrar office, if the vendor fails to appear to perform his part of the contract then sue them for specific performance or damages in lieu of the failure to perform the contract.
Feel free to contact on [deleted] for assistance.
Kind Regards
Setu Niket
Advocate