Dispute regarding the real owner

I have purchased a plot in year 2016 in West Bengal. After a year when I start to construct a boundary over the said land somebody came and stopped me by saying this property belongs to him which he had purchased in year 2007. He got mutation from municipality. At the same time I also get mutation from municipality as well as from Land revenue office but he doesn't get the mutation from land revenue office. When I checked his papers I came to know that he had purchased the property from the same owner but having different face. Further I also came to know his registered plot no is different than me even the municipality mutation has different Holding number. They charged 144 against me but the case was dismissed in case after 3 to 4 hearing. once again when I m trying to construct the house they are claiming the same. How can I come out of this situation?? One more thing I had searched the registration for the said land through local lawyer and even I have taken a plot loan so they also searched for the same. But nothing came in searching.