Grandparents land dispute

This question is raised on behalf on my grandparents who has a house property in remote village in Tamilnadu. A dispute was raised by the neighbourhood on the above mentioned property around 7 years before claiming that certain portion of our land belongs to them, where we have been using it for almost 40+ years. There was a case filed in the court and the initial judgement came in favour of our neighbourhood mainly because our lawyer took some bribe from the opponent party and favoured the opponent party. Later we appealed again the got the judgement in our favour 4 years back. We waited for 1 year period for the opponent party to appeal further, but that didn't happen. When we tried building a wall in the land area which belongs to us, but our neighbourhood person raising voice against us not to build the wall as the land still belongs to them. We tried getting help from the local police to help build the wall, but they are advising to measure the land again with the help of government surveyor and build the wall, which I strongly believe that there are high chances that our neighbour would bribe the surveyor and measure the land in favour of them. Can I have a guidance from legal side how we can proceed on this?