Bajaj Finance — threatening calls from bajaj

I have taken a laptop using bajaj finance 10 years back. I have paid the first emi through cheque and paid all the remaining emi's by cash as they had some problem in clearing the cheques. I also have got receipts from the representative for all the payments and the loan was closed. After one year, we got a call from them stating the loan was not closed and final emi is pending. We have visited nearest branch in tirupati and submitted all the payment receipts and got confirmation from them saying they will close the loan. Now after 9 years we are getting continuous threating calls from customer care asking to clear the due and failing to do will send us to jail.