Ancestral Property in Tamilnadu

Dear Sir, I have here to ask a clarification regarding share in ancestral property in tamilnadu for my mother. The property belongs to my great grand father and now there are totally three grand sons and two daughters (My mother is one among them). My grand father died in the year interstate during the year 1982 with out making any will and my grand mother died in the year 2000 interstate.My mother married in the year 1978. Only when my mother and her sister asked for the share in the ancestral property my uncles decided not to give any share to my mother and her sister they partitioned the land between them during the year 2017. (Only a part of ancestral property has been partitioned so far that too in the last year only) And my question is whether my mother and her sister have rights in the ancestral property. Whether we can able to file a suit against the property as we have all supporting documents such as my grandfather and grand mother death certificate,Legal Heir certificate.