Course of action in case of false allegation filed on court by opposition

Hello Sir, I am Gaurav,my father has 2 acres of land which he purchased from Miss Anjali in 1990 and we have the actual papers of the property which was handed over to us.The man who was residing there for a long time is claiming that the land was bought by his father long ago,though it is false allegation made by him since he has no real papers or documents of the land.So he filed cases one after other, at first district court then high court.Morever his lawyer is helping him hugely for 25 long years,well i'm agog since i think his lawyer is also hoping of taking our land,well i don't know what is the purpose of both of them doing this since the real papers are on our side,moreover since he has no actual papers so he was unable to show the later on the court so he took false leaves in every case dates.In god's grace we won the case in judge's court after 15 years and now the case is going on in high court,now he is threatening us that if we win the case on high court then he will go to supreme court.Since we are on huge debt so we can't afford further money for running the case on high court as well as supreme court and earlier also we paid huge money for the case dates on above court.We thought of selling the land on today's date and thought of being debt free but now we are having a very hard time since we took money from other peoples on the hope of solving the case and repay the money once the case is solved, and now we are ending up on paying interest to every person from whom we took money and moreover no one is taking the land since the case is going on.So what is the action that should be taken to solve the case as soon as possible.?? Thanking you and eagerly waiting for your precious reply.