Mutation of ancestors Land

Hi My Grand Mother has left the property in Patna-Danapur, India in the form of Land the Land is not at a single place, its situated at 4 places in different sizes When she was alive, 4 Sons of my Grand Mother made an Affidavit for the distribution of land once my Grandmother passed away, we tried to do Mutuation of Land to make the portion official, but we came out by our Uncle(one among 4 brothers) that the tax or fee which need to pay for the land is not paid for more then 10 years, and whatever paper which we have its not tally with amount of land which we actually have the paper states that the sum of our total piece of land is lets say 9000 sqft but in actual we have around 14000 sqft(in actual means we have possession of 14000 sqft land from more then 50 years) Do we have any procedure in any department who can make the land official now and can do the official mutation. we check the office to get this record from office but no chance, the officials are telling the file is missing. our land is also not showing in online land mutation of Patna website please help me to what should i do in this case to make our land official. Thanks Modak