Lost loan account.. Poor service delivery

The service they provide is extremely poor. I had 2 loans with them which one is paid up. I called to settle the second one nobody seems to know where the account was handed to. They gave me false info that the loan is with mbd which it's not true mbd doesn't have my second loan. Cindy Martin who is apparently the one that deals with these queries she is not responding to my mails,neither is their complaints department. I need a settlement letter so I can pay off the loan in full. Very disappointing such a big company