Worngly purchased mortgage property by ny late mother

My mother had purchased a plot with constructed house in Vasai - Virar from one M/s. Parimiti Buildicon in the year 2007 by a registered sale deed. It was a scheme of around 52 bungalows on the plot. Later only 6 plots with houses standing in name of the builder were abandoned and still exists. In the year 2014 around, my mother received a notice from a bank for taking the symbolic possession of the same plot which she purchased. She immediately filed a police complaint against the fraud and also filed an intervention application before the DRT court before the recovery officer. Thereafter, all the plot with bungalows scheme was controlled by the society formed by the members of the society, also deemed Conveyance was also transfered in favor of society, now it seems the builder has ran away and is already in jail for doing many more such type of scams. While going through the DRT proceedings, it was found out that in the year 2004 he had sold the same plot with house to his wife also, and her wife has taken a bank loan by mortgaging our plot with house, it seems the recovery officer at drt seems to be not deciding our application in our favor, so kindly assist what needs to be done now. Search report shows the builder sold the same to his wife in 2004 and to us in 2007. Now my mother has expired. Kindly assist what needs to be done to save out property from the bank to get it auctioned for recovering their dues about principal amount of Rs. 13,00,000/- apprx. I am not in a position to repay the loan at all. Also it seems that builder has taken loan from some other banks too on the same plot and I had received a letter in 2014 but thereafter till date no action has been taken by that bank also. What shall be done next now? Please guide and assist asap to resolve this issue. I have understood now that my mother was been defrauded and she has been sold the property which was already mortgaged. The builder and her wife and his associates all are in jail. Builder name: Anand Uttam Kadam, her wife name is Kavita Anand Kadam. They have been arrested by EOW in Navi Mumbai mostly. There are so many frauds done by both of them, Google it u will know their lots of frauds done.