FNB took my money

I withdrew r5000 from a cash express atm with my FNB account on 7th of October and the money didn’t come out of the atm,I emailed FNB and they reversed the money today into my account but they debited the r5000 again and when I contact FNB about the issue,no one is willing to help and they keep telling me that they will look into it..it’s been three days now and I need that money like yesterday…I don’t understand why FNB will reverse the money into my account and debit it again