Property Issue related to Land (Khet)

Hello Sir/Madam, I am Having Land (Khet) in Village near Nagpur area. As it is on my Grandfather Name. But this land was disputedly Registered by any other person in 2008 by showing fake details like election card and fake person same like grandfather (fake person) at the time of registry. but election card was invented in 1995 and my grandfather was died in 1993. but election card was invented in 1995 and my grandfather was deied in 1993. As my grandfather was died in 1993 and this property was selled in 2008 by that person. And after he sell half half land to 2 another person in 2009 and then these both persons selled this propert to another single person in 2010. 7/12 is on this new person. what can we do to cancelled all this registry.I withdraw all registries and documents related to that land from tehsil office.