Fraud in property registration papers

We have sold 3000 sqft property with house in 2009 with my mother and 2 sisters. at that time the buyer made agreement for 25 lakhs to purchase the property in that agreement they have taken sing from my mother.. while registration time in registration paper they have mentioned 78 lakhs rupees have given for the property to purchase.. at that time we didn't check the paper they asked to sing all 3 daughters with my mother.. directly all four members have signed.. my mother is uneducated and we were studying in college at the age of 21 years.. we also didn't know about the problem at that time.. after 2 years we came to know that they are taken sign for 78 lakh rupees they have mentioned cheque numbers and DD numbers also but we didn't receive any of that only we have received as per agreement amount of 25 lakhs by the way of cash.. we have talked about this problem with so many lawyers in Bangalore everyone is saying u can't do anything because of sign in registration papers.. in 2015 i came to know that the person who has taken my property he has taken loan from bank for buying my property which mortgage for 46 lakhs.. I have talked with bank person he said that person is missing.. after 15 days of registration he s missing till now.. because of that they have action my property and sold for 80 lakhs in 2015 January.. buyer taken loan on my property and given 25 lakhs to us balance 21 lakhs he has taken and the property also get registred in his name and then missing.. i dont have any option to show that person made fraud to us legally.. we r three daughters our father passed away while we were studying we don't have any supporters in our home only we are four ladies.. my sister got married me and my younger sister are there with my mother.. now we are in rented house we dont have any other source to settle our life.. so please give me any solution is there for recover my home.