My right

My nanna purchased and left a property where i and my mother used to live till my mother died. my naana died without executing any will. he had 2 daughters only. my mother too is no more. post death of my mother my mausi got our hugely built house abolished and got a mall and nursing home constructed there and is denying my share in this ancestral property. on challenging in civil, criminal and revenue courts she has responded that my late naani left a registered will in 1982 by dividing the property 1/2 & 1/2 to my late mother and my surviving mausi. she also claims that my mother (who was bed ridden) and all alone in the property post my marriage too left a registered will giving her 1/2 share to mausi's son, which according to me is not possible and not in my notice. my mausi also claims that my late mother rendered will in my pressence in 1996 which is totally false. my mother was widow bed ridden and had two daughters only myself and my sister. while my mausi is financially very sound and is a doctor. i wish to know whether the will if executed by my mother has any validity. my mausi has got the property mutatated in "nagar nigam" on name of his son " through adhyaasi" and has not submitted any papers and in "katauni" the papers are still on the name of my late naana!! please do advice!!