Fraud in property transfer by siblings

my father has three brother and my father is oldest. we were living in joint family till 1998, in the house that we( my father, mother & sister) are living now is owned by my grandmother. During the period we were living in joint family our family build new banglow of two floor and it was on the name of my father till 2013 . in 1998 joint family seperated and my two uncle decided to leave in new banglow. my grandparents also living with youngest uncle in new banglow. In 2013 my two uncle decide to sell the house but that was owned by my father. that time my father agrees to transfer banglow to my uncle's name in one condition if my grandmother transfer the house to my father's name that we are living now.after that my grandmother told to my father that no need to transfer due to cost then she made regesterd will on my father's name and my father transfer that banglow to yongest uncle that sold in 2013.now my grandmother cancle that will and told us to leave the house." what to do now?