Notice

My father left 4 acre of land My father died in 1973. Total 7 heirs 5 sisters and 2 brothers including me. Release deed was made in 1977 September and all 5 sisters released their rights. After that land title remained on me, my brother and my mother. Mother died in 2000. Land partition was done between me and my brother in 2005. Now my all 5 sisters have send notice to me and my brother to claim their share from the land. In notice it has mentioned they have not signed any deed or were send any notice by mamlatdar to then and if unaware of laws at that time ( 1977 ). When release deed was executed in 1977, they were send 135 d notice and release their rights in front of talati / circle officer and in presence of more than 5 witness which is mentioned on VF6 ENTRY DETAILS, they have also have had made appeal to mamlatdar / collector not to consider the elapsed time ( 39 years since 1977 september ) and be lenient. Since 1977 they have never claimed in court or raised any issue in the court about this land now all of a sudden they want their share. can you give your expert advice