Unhappy client FNB Loans

Good day

On 16 February 2018 I called FNB loans for balance on my loan account and I paid it then the money was paid back into my account so I went into an FNB bank at Atteridgeville branch on 20 February 2018 to find out why it was paid back into my account and I was told the account number I used is no longer working. The consultant dialed a number for me to speak to another consultant and I was given the balance of my loan and I paid it immediately on that day inside the bank I made a transfer and send proof of payment to ********** as I was told, now when I request a paid up letter through my Debt counselor I am told that I have a balance of R15 that I need to pay before they can send paid up letter.

Please advice on what to do.