Surrendered Vehicle auctioned and balance amount is being demanded

I had availed finance of Rs 501000 from Tata Motors Finance Limited for hire purchase of a car for commercial use a cab. after some months I could not pay my EMI on time as I could put enough hours do to health issues. some how managed to settle a few EMIs and finally became my means, the finance company was in touch with me regularly after they came to my house and asked me to surrender the vehicle which did they asked me to pay the pending EMI and take the vehicle back I failed to do so since this was my only source of income. and after a few days I had been hospitalized for fifteen days , a bout of Pneumonia and Heart failure like condition. I received a loan recall notice and termination of loan and invocation of arbitration, asking me to appear in front of the advocate. After some I started getting call of settlement of the loan amount as they have auctioned my vehicle and they have incurred a loss of Rs 2 lacs and I should pay the balance amount. or face leagal action.