Harrassment by the Recovery agent

I took a Two Wheeler loan through citi financial more than 10 years ago . They also offered me a personal loan against that . I was clearing all me dues. Then I did a top up for the loan and still continued to pay the EMI. at the end of the loan I could not pay the emi due to financial crises in family . After some time this financial institute got closed and I could not pay them off. I could not approach anyone. As years passed by I stopped receiving any calls from them. I tried for a personal loan from other Banks but could not due to bad Cibil scores with citi. But I could to find a way out how to reach them and pay them off and settle the matter. Now after 10 year I started receiving calls from Kotak Mahindra Bank stating that I them Money. I was shocked to hear them. They say that they have taken over the Citi Finance and now I need to pay them. I said ok and asked them how much do I need to pay b, I din't know what to say because the amount they mentioned was way too much. They still added the interest for all these years even though the institute got closed. How would I know that. I told them to settle the amount but they are stuck to that amount. My husband is a heart patient , now these guys are extremely abusive. whenever my husband picks up the phone they are very abusive. We stopped answering then they approached by office . They are calling all my managers and HR Male and abusing hem over the phone badly. They even read out their address. I and my family are mentally harassed and don't know what to do. I also agree to settle the amount but they are stuck with 1 amount. Please advise what to do. I am the only earning member in my family. My husband is not keeping well and have 2 kids also to take care off.