FNB withholding money that was mistakenly transferred into a wrong account.

I accidentally transferred 18000 into my loan account instead of savings account & requested a refund which I was promised will be done within 5-7 working days which never happened & when I enquired I was told consumer legal stopped the refund since the loan account was in arrears but nobody bothered to inform me. now my family & people who rely on me are struggling because FNB is withholding the money. Rent, transport ,school fees are not paid even grocery was not bought but it seems like nobody at FNB cares except for the arrears on the account. I've been a FNB customer for than 12 years & now thinking of jumping ship & depressed how I'm going to survive if I don't get a portion of the money back.