Car loan after death of borrower

My mother took car laon in March 2017 from private bank. In the Loan agreement there are no Witness / Guarantor / Co-Borrower. My mother passed away in Jan 2018 post which we got to know about this Loan, as stay in a different city. We wrote to bank asking abt the agreement copy in April 2018 which is till date not responded by the bank. we donot have the possession of the car. The bank collection team has been after me and father to clear the dues. Arbitration is also enforced on us, which we attended but the neither the Arbitrator nor the bank was present. The bank is demanding Rs 9.7 lakhs including agaisnt the prinicpal of Rs 10,77,000 ( 14 Emi of Rs 22k has already been paid by my mother). As 1 time settlement in good faith we have offered the bank Rs 5lac which the bank is not agreeing. what should we do ?