Elder sister registered father's property in her name & denying share

Sir I am a Hindu girl. We are three sisters. Actually my father expired when I was right years old. Now I am 21. The land in which we are staying was bought by my father... But as some dues were left, so the documentation process was not done but after my father died my brother in law along with my elder sister went to the owner and paid the remaining 10000 rupees and asked to complete the documentation process. The owner was about to write the property in all the three of us names.. but my elder sister told that she would take a home loan and build a house for us and so she asked us to name the property in her name.. so we agreed and the owner named the property in her name. But now she is neither taking any home loan nor making house.. she even threatens us to not give the property back. So what should we do to make the property in the name of three of us..my mother is also alive us well.. now we are suffering lots of problems..kindly help