Buyer has planned to take our property by managing legal experts

Sir We had joint property by name of my Father & me!In 2010,my father did sell agreement in 21Lacs,taking 2Lac token, on 100Rs stamp My father or Buyer or Buyers person would have signed agreement on behalf of me probably A past Civil suit is there on property by last tenant of property, from past 14years,still my Father sold that property When sell agreement of property is done,property was modgedged in Bank due to Loan Initially, Buyer has promised orally,that he will give 10 Lacs,so that my Father can clear Bank loan & get the property free for transfer But after agreement, Buyer refused to pay 10Lacs So my father cleared property from bank in 2012 on his own Later he sent a notice to buyer,not interested to sell property now,take your money back In 2013,Buyer filed a suit against us,for transfer of property! No notices had come to us,Buyer managed it all In 2015,We got to know from well-wisher, case is filed against us!My father filed an application, saying no notices we got & want to participate On 26/7/2016,Our Lawyer called us & told, application rejected & have to go to High Court Please help & Guide, what to be done further