Sale deed validity

Hi, this is regarding the agriculture land's (plot) sale deed agreement, which I have made with seller 3 years ago. I have paid the 93% of the total purchase value at the time signing the agreement and also have registered the agreement with the local sub-registrar's office. Since then seller has failed to complete the final registration despite constant follow-ups and reminders many times. He kept on buying additional times (whenever he failed to keep his promise to do the registration) whenever I approached him. Finally last year we have mutually signed another agreement as an addendum to the initial sale deed, which states that the seller has no obligation in me taking possession of the said land/property, and may be used whatever way I wish (I have setup the fencing around the site after taking the written consent of the seller), and for that I have also paid the balance 7% of the due amount to the seller, which concludes the full payment and no dues from my side. Am now concerned that as there is only one month left (as I have been told that the usual validity of the agreement is 3 years, but the agreement has no timeline limit specified), what happens to the sale agreement if the final registration is not performed by the seller within next one month and what are the possible consequences and remedies. How will the court treat my case, if I have to approach it in future (just in case I get cheated by the seller, although he don't look like that, but still in any case - as I can't read his mind...)