FNB get back to me ASAP!

I took out a loan 3 days ago, only for half of the loan to be deducted as loan repayment + interest? As far as I know i atleast get 30 days to pay back, and actually be able to use the loan!!!!!!!!!! This is not the first time that FNB just took money from my account! I don’t know why i stay with this ****** bank.