Partition Of Ancestral Property

ancestral property was divided among my father's 6 brothers verbally by the village mukyas, in year 1995. however papers has not been made. at that time all the 6 brothers are living together in same house. now after 20 yrs of that division, the land which came to my fathers share, we came to know that it was on his elder brothers name.my father was ploughing that land for last 20 years. and also it came to my fathers share. so tell me what can we do.