1. Palak and Paneer had perfected their title to the land by adverse possession (1966 to 1983). Their occupation of the land was for more than 12 years to the knowledge of the owner MIRCHI.
2. Mirchi has not raised any dispute against the title claimed by Palak and Paneer, as can be made out from your query. Mirchi has also given the original title document in his name to Cabbage, implying that mirchi has no claim or interest in the Land.
3. So palak and Paneer would become co-owners of the land by adverse possession.
4. Palak and Paneer then sold land to Cabbage under agreement and a registered gpa against consideration. So they received their consideration for the sale of the land to Cabbage. So cabbage becomes owner.
5. Now once palak and Paneer have sold and given up their rights in the Land in their respective lifetime, then their legal heirs have no business to challenge the sale effected by Palak and Paneer. Palak and Paneer were owners of the land and they could deal with it in any manner whatsoever in their lifetime by selling or gifting or willing away the same. The legal heirs have no say in that during the lifetime of palak and Paneer and after their demise.
6. The land already having been sold by Palak and Paneer in their lifetime, then nothing survives for the legal heirs to now challenge such sale.
7. It's very clear. Owner can do whatever he wants with his property during his lifetime. After the owner dies, his legal heirs cannot all of a sudden surface and challenge the transactions done by the owner in his lifetime. Any such action is bound to fail in a court of law.
8. Worth noting that Cabbage's name also got mutated as holder of the land and he also won against the govt in the Land acquisition matter. Had the legal heirs of palak and Paneer had any right in the Land, the govt could have fought against them in the Land acquisition matter and not with cabbage.
9. So the suit filed by legal heirs of palak and Paneer is bound to fail. You can immediately make an application under order 11 rule 7 of CPC for rejection of plaint since the plaintiffs do not have any cause of action against you. Also raise the preliminary issue of limitation that the suit ought to be dismissed on the ground of being barred by limitation. The transaction between palak and Paneer on one hand and cabbage on other hand, happened in the year 1983. And the legal heirs are filing a suit now in 2018!!! Is that some joke?!! It's clearly barred by limitation
10. So before any hearing takes place in the matter, I advise you to immediately file a notice of motion to reject and dismiss the suit on the grounds of 1. No cause of action and 2. Suit barred by limitation