Mortgaged Property

Badly in need of your advice please My father mortgaged his own property where we all reside, for an amount of 20 lacs by March 2016 to help someone for which no record found. He is missing for 5 months - FIR filed. Now mortgagee insists me and my brother to pay the loan amount along with the interest due of 3% which works out to Rs.60,000/- x 19 months. The mortgagee says that the loan has been registered for Rs.5 lacs for which I had taken extract from Register office and balance Rs.15 lacs was not registered. We are from middle income group who couldn't arrange for huge amount and we don't own any other property to mortgage and settle the loan. Both of us live together in the same mortgaged house and our net earning is Rs.45000/- only. The extract of registered document for Rs.5 lacs says that the mortgagee legally act against the property if the loan amount and interest amount was not paid within 2 years. confused state. Kindly advice in this regard how to handle the situation. Property market value 65 lacs