My Plot Grabbed by some people

As we complaint at police station regarding our plot grabbing but police didnt take any action and took long time and in between the land grabber got house tax receipt from village talati....stating that the plot is his and took a bail and went to court. Now the land grabber filled case against us stating that the plot is his. As we have original land purchase deed and land record paper got it from land record office. The plot is very old since 1939 which was given by Maharaja to my grandmother's father to my grand mother. My grand mother expired on 2003 and we didnt transfer that plot in our name till today and it is in name of my garndmothers father but we have taken the sign of all nominees and all people related to the plot in notarized. We have also sent application for transfering name to mamlatdar but they didnt take any action but we have that paper signed by mamlatar. When the case was running my father also expired. As the case is on us me and my mother. Pls guide