Unauthorized debit orders by FNB

FNB does not seek your authourisation to debit your account. They just drain your bank account even before your monthly debit orders can run. This to me is cruel as if the authorised debit orders are unpaid due to insufficient funds; it is FNB which will also charge me for unpaid debit orders. They make more profit by debiting without prior arrangement so as to gain profit. Dissapointed