FNB Took my money

I had my fnb account debited on the 20th of December instead of the 26th of every month, without my permission. I queried this with my premier banker Portia and she said that her manager Rethabile will contact me. That was at 7am this morning and I am still waiting. How can fnb just take our money without our permission. And they refuse to refund my money today. I am sure that I am not the only person that fnb has done this to.