Debit order went off wrongly, not refunded after 7 days

I had a personal loan with FNB. I settled my loan on the 21st of November, however my debit order still went off at the end of November (R1 900). I contacted FNB immediately once the debit order went off on the 29th of November. They told me that they need at least 10 days notice to be able to "cancel" a debit order from going off, which is understandable. They then told me that it would take 4-6 days for that amount to be refunded into my account. Contacted them again on the 4th of December, same story. This time the person told me it takes 5-9 days. It is now the 7th of December and I still do not have my money back, and R1 900 is a lot of money for me which I really need. How hard can it be to press one button and refund someone for the money that you wrongly took out of their account? 9 days?