How to get a permanent residency card if we have possession of that property for more than 30 years?

We bought a home 30 years back, gave some amount and documented that deal on a bond paper that such amount has been given and mentioned remaining amount to be given.. As the time advanced we had given the remaining due amount, but we haven't registered that property in our name.. Unfornately the real owner(Mr. X) died, ten years later we started renovating the house, the paternal relatives of the Mr. X came and started quarrelling with us then lodged a complaint against them in local police station, chapter case sheet was prepared against those relatives of Mr. X, now again we have started renovating our house then that relative of Mr. X sent a guy with a document mentioning that they are the true owners of our house if want to sell us then we can give you a handsome amount. But we refused that offer as we are emotionally attached to our home, what can we do now all our electricity, water utility, property tax bills are in the name of Mr. X's wife's name, but we are paying those bills without any lapse through bank cheques.. What can I do now to claim ownership of this property and get a permanent residency card or get registered my name in City survey office for this property???? . Also I doubt that documents genuineness, as they are wards of Mr. X's real brother, and reason mentioned in the property card was property title given according to the will of Mr. X's brother, but how can this be possible if this property belonged to Mr. X... Please throw some light into this matter... Thanks.