illegal partition and construction on ancestoral property

Dear sir, my grandfather has left some property which he got from his father. now my 2 uncles started construction on high value plot and giving my father a very low value plot. my father is agree with them. but i want equal value partition. what can i do?? feom where can i get stay order against this construction? my uncles do not have any ownership papers and passed map of nagar parishad. what papers i need to get stay order??