property matter

Property is purchase by my father in Bilaspur Chattisgarh in the name of mine when I was 20 years old (now 31 years old).   The registry paper  of the property was stolen by  my 2 brothers from my father. My father lived with me  (nobody take responsibility of him) in kolkata for 11 years who was expired 2 years back. Now my brothers who lived in that house in bilaspur  are not willing to give any share they told i have taken my share. They said my father sell another property in chhattishgarh and as my father live with me he gave me the money of that. i take my share from that. Which is not true (giving money). They send me a legal notice that i have taken my share of property as father buy the property it is their and my three sister's share of property,so if I  send any agent to sell the property they will go for legal action. Are they have any authority to take legal action against me?how i get my registry paper back?