Blocked account for no reason

FNB blocked my husbands account on the 17th WITHOUT notifying him, because of a R200 payment i made to his account. Yesterday, when wanting to swipe the card, it kept declining. When he phoned they said it has been blocked, and could take up to 30 days to resolve the problem. And that they cant help him now, only on monday! How does one buy groceries, and do what needs to be done?