Sale deed on behalf of power of attorney

Hi , my grandfather made a power of attorney in my brother in laws' favour in 1991 to make a sale deed. After the sale deed he changed his mind and put a complaint to stop mutation . Later he also put a criminal complaint against me. He then made a will in servant 's favour, but later after 6 moths he changed his mind again . He cancelled the old will and made a new will in my favour. Lower court has given the decision in my favour on behalf of sale deed. But servent made a appeal as LR in district court. District court has given the decision in favour of my grand father. Who has been died 23 years ago. I appeal the highcourt but same decision in favour of my grand father. Now please let me know can I cahallenge the will which is in servant's favour? We are three persons who are entitle to get that property as inheritance . One is my grandfather's daughter . One my sister and one me . Should we go to Supreme Court or start a new civil suit in lower court under succession act . Pls let me know .