Debit oder reversal

been trying to reverse a debit oder that is not authorised for the past week and been given a reason of "system errors and debit oder is not showing up on my account " this has been going on for a week were they claim that the is a problem with the system . but there has not been any communication regarding this or any form of information what is going on! this is really bad services where no one at FNB can give me solid answer and I keep getting multiple reasons why I can not reverse my debit orders.