Got less property share of my father's ancestral property after my father's death

My uncle cheated us while distributing ancestral property of my father share .when partition happened ,my father died 6yrs before and my mother didn't know my father's property ,but in partition deed my mother signed in 2007 .my father was elder sold and he got only 3900 sqft ,but my uncle got almost 20000 sqft sites ,the partition happened in civil court and my mother was blackmailed to sign the deed ,my uncle told if you don't sign then you won't get any property.so can we challenge the partition deed