Legal option for agriculture fraud

I have a situation to explain. (This event happened in Ghazipur district of UP) My father are three brothers. Back in 1999 my father had urgent requirement of money to pay the admission of my brother. He sold his portion of land (8 biswa (approximately 0.1050 hectare to another guy X in the village. He took the advantage of situation and only paid very little money. (Lets call this land A) He is cultivating that land since then. We moved on and got busy in our life. We moved out of the village and only my grandmother and aunt were living in the village. Our agriculture land was given on batai syatem as we don’t had water supply system. Recently in Sept 2018, we set up a water pumping system for water supply and build a room for storage on the adjacent agriculture land which is approximately 0.3010 hectare and was co-owned by my grandmother and two uncles. We spent 7 lacs on this. (Lets called this land B) Guy X is claiming portion of land B, on which the irrigation system is setup belongs to him. It was very surprising for us. We checked land B Khata and Khasra information and found his name was there on the land which was co-owned by my grandmother and two uncles. We also found that, my grandmother and uncles name are there on his land (A) as well. Looks like during recent chakbandi (which I believe happened in between 2010 to 2012) the guy x and my grandmother, uncles name went on khasra belongs to land A and B. and since, no one from our family was in the village, no one noticed. In short - 1. Situation before chakbandi – 1.1. Land A (size 0.1050 hec) : Father sold land to Guy X in 1999 1.2. Land B (size - 0.3010 hec) : : Owned by my grandmother and two uncles 2. Situation before chakbandi (somewhere in between 2010 to 2012) – 1.3. Land A (size 0.1050 hec) : Co-owners - my grandmother, two uncles and Guy X 1.4. Land B (size - 0.3010 hec) : Co-owners - my grandmother, two uncles and Guy X Issue : Guy X secretly transferred portion of land without discussing it with existing co-owners and claming the portion where pumping set and store are constructed. Can you please advise us how to proceed on this and make him legally accountable for his actions. Here are some of my points which I think we can use to take him to the court 1. Guy X somehow put the bottom portion of the land against his name without any mutual agreement of all the co-owners which I think is a case of fraud. It should be fixed and he should be accountable for his action. 2. Guy X was cultivating the land A since from chakbandi without sharing any earning with co-owners. Can we put stay order on Land A and claim earning from the shared land? 3. We spend 7 lacs for installing pumping and storage room. Guy X haven’t disclosed it at the time of construction and only claimed once the construction was done. Can we claim our expenses and compensation of stress caused because of this? Looking forward for advise.