Settled personal loan & still being charged

I took out a personal loan. Was able to settle it early. Paid more than the balance owing. The following day an amount showed owing. I paid that amount. Three days later another amount showed owing. I paid that amount. Phoned Nedbank & was told I should have a requested a settlement amount. I then requested a settlement amount and was given a letter showing 0 balance, 0 interest, 0 installment. A week later the account again showed an amount owing. I phoned Nedbank and was told that the account was still open and I was being charged for debit order, interest and admin. Can you believe this? What next? Said they will close the account and request a refund. Will wait and see.