.1 It appears thelamd belonged to your maternal grand parents.
2.if that sis o then your mother have exclusive title over this and the concept of ancestral proeprty does not apply for female.
3.SO if your mother willingly transferred the properties to your sister you can do nothing about this.
4. Your sister have valid title in the proeprty and no amount of challenge from your end can make it defective.
5.Recording of Revenue Records does not change title in the proeprty.