Land not registered legal heirs of previous land owner claiming share

dear sir/Mam, My grand father bought two pieces of land in 1973 and 1975 ,he registered first bought land(1973), but unfortunetely he forget to register second bought property(1975). so we are now in Appeal in the court of DSLR District Supredent of land Records. the Nominees of previous land owner is now claiming their rights belongs to that property..now near about 40 years are passes we r living their .we have all buying documents.all munciple reciepts,all tax reciepts of land ...so what we have to do now ?