Actual possesion

Hai, i"m Anbarasan from tamilnadu. We purchassed a land by 1988.And subsequently we bought a adjucent land by 2005.Currently we applied for subdivsion.We came to know a part of our land was under actual possesion.A tree was there. But with the mutual aggrement we eveacuted everything and surveyer measured and he fixed the bounderies with stone. When we plan to construct the wall they are not allowing us and they are giving problem. As per FMB copy and our primary register document everything is very clear and no mistake from our side. But our opponent have made registration with wrong measurment.He bought the land after 10 years of our registration date.In the FMB his boundery measurement is only 118 feet.But he mentioned as 141 feet and got registerd. Moreover our lands have totally different survey number.His number is 145/2A, Mine is 145/9. The only thing is ,his land located at the backside of our land.Moreover we noticed that between our land and my opponent land there is a empty space of about 10 feet is there as per FMB and as per actual survey which is excluiding our land area..Our opponent have one more issue .He mentioned wrong subdivsion number in his registerd sale deed i.e.145/2B for which he has to go for rectification deed again. Irrespective of these things ,the opponent pulling us to the court.He gave caveat notice against me. We are planning to construct house in that land.Though the documents are in favor of our side this person is not allowing us to bring in enjoyment of our property.What shall i do during this situation?