specific perforance act
i had registered agreement with farmer but farmer had sold out land to any another person.
You need to approach the Court for enforcing the clauses in that agreement. But before that please ensure that the agreement is registered and valid.
Nevertheless if the agreement is not registered, can be take up as evidences though is a very cumbersome process, provided there were one or two witness signed in that agreement, and if required they can come in the Court to record their version.
Apart, it is preferable to send a Advocate's notice on not honoring the agreement with an ultimatum to enforce the clauses.