Will written by my mother seems unfair what can be done

We are (Hindu) 7 members Father(Rtd pensioner), mother (late), my self son married, working in a pvt co. at chennai - one son; followed by 4 sisters. all natives of Rajahmundry.1st one divorsed stayed with my mother; 2nd. Married - 1 daughter; 3rd. Married but no more - 1 daughter and 1 son; 4th married - 1 daughter and 1 son. Mother left a will written by notary..three houses in the name of my mother were given to my sister(divorced) leaving others with nothing. There is no consent from father, my self. Will/notary was witnessed by maternal uncle and aunty. Now my sisters don't want to give me copy of will and not revealing any details.I am feeling decieved. My father supporting will. I am contending for equal portions to all incl. 3rd sister who is no more. Pls advise.