Incorrect transfer from a FNB account to a FNB account takes 5 - 7 working days to be reversed

I made an unfortunate error and transferred funds from a transactional FNB account into non-transactional FNB account. I immediately phoned the call centre to get it reversed as I need to use the funds to pay my accounts as it is month-end. Although the call centre was very helpful it takes 5 - 7 working days for the money to be reversed. How is that helping clients?