The disputed property is ancestral property

Sir/Mam, (Query regarding property of hindu family) My mother is 66 yrs old and she has 1 sister and 5 brothers.My mother's parents died. (Father died in 1945 and mother died in 1999) Now the property is house and some open space (approx 1.25 guntha). One of my maternal uncle fraudly became the owner of that property by giving affidavit to land records dept. stating there is no one heirs except him and later he gave that property to builder for (joint venture) when we came to know about his fraud and when claimed about our share then he denied to give share and contended that my mother and my mother's sister has no legal right to claim. Is there any solution ? Pls suggest me Thanks in advance