My father gave property to son of my uncle. How can we claims over pro

Sir we are four sisters. My father gave all ancestral property to my uncle's son in Aug 14.he made a degree. At that time he also assured my father n mother to take care in old age. But after marriage my uncle son did not fullfill their requirement and start annoying them. At that time uncle's son take fraud signature of my two sister at home by telling that these are signature for govt help for girls( Ladli yajna). They were going to school and did not read documents.Now my parents and we all sister want our property back. Sir give us advice what we should do.