Options for buyer for a Time lapsed sale agreement

Sir, My wife entered into a Agri land purchase registered sale agreement in Nov 2013, paid 93% of the value of the agreed amount to seller. Since the land records were not correct in Government records due to mistake done while updating land survey details by Govt employee much before we entered into sale agreement, we couldn’t go for sale deed. Seller agreed to get the records updated at his cost within 2 years & inform us. but he did not even submit application to correct records till date (Aug 2023). We are in constant touch with seller for all the while, he gave assurances but nothing is moving. Now he is demanding current market rate. We are about to send legal notice to seller but do we hold any chance in law? Also he intentionally did not mention his minor children details in sale agreement. Is this not a breach in 2 counts? Of course we had difficulties as we misplaced originals & recovered those recently which is also the reason for our inaction (legally) for many years. Can we file a case on specific performance clause as seller failed to perform his duty within agreed 2 years & beyond? Is there any legal remedy for our unique case? Thanks