Cancellation of Release Deed?

My father have one younger brother and four sisters. on 2009 our grandfather property is on under some problem with mortgage issue with bank. on 2011 My father and his brothers and sisters released their mother's land to a one of their sister without getting single penny. The purpose of release a property for court expense. she also gave a word i will takecare of you & this issue. within a one week she transfer this property to her son with settlement deed and pledge the property and they build a building. They didint pay the amount on court, they pay after three years from the date of release. on 2019 our grandfather property got under possessioned by bank in the reference of you pay the amount on delay process. After realize this my father and uncle asked her you didint pay the amount on right time so cancel the release deed or return the money. she disagree & she talk differently rude i will not cancel the deed and also am not giving you a single penny wherever you want to go i will handle she said. S0, what is the further proceed to claim our rights on that property?