STILL WAITING FOR DEBIT REVERSAL

I settled my personal loan with FNB on 24th September, and was debited on the 25th for the installment which I understand. I was then told to call within the next week to get the debit refunded back to me. To date I am still waiting for the debit to be reversed. I have called numerous times and got told to wait 5-7 days for the refund. I AM STILL WAITING!!! HOW IS IT POSSIBLE FOR AN FNB TO FNB REFUND TO TAKE THIS LONG!!! THIS IS UNACCEPTABLE!!!!