Bank recovered debt by mortgage asking for difference amount

Hello Experts, I moved to overseas for work purpose since last 4 years. Before I left from Mumbai due to some circumstances I applied gold loan from Muthoot finance. I failed to pay my interest and rest of the money. one day I asked branch manager (on phone) that,” what happens if I failed to pay, he said you owe less amount than your gold valuation so we will auctioned your gold and will take our money. 1) 2 years later I call ,that Branch manager left that branch & they are asking difference money ? How do I settle this matter as they are adding up new interest on that remaining amount