wrong account adjusted because the system(postillion) was offline

Hi,Capitec Bank,took R500 from my account and I was told that It is an adjustment that was made due to the system(postillion) being off as a result.Is it my problem that the system was off ?I made a payment R500 and I was charged twice (because R500 was taken as an adjustment as per the sms).I complained about this almost three weeks ago and no one called me as yet except an attempt to sell me a credit card.how do I trust you guys with a credit card if money erronously goes off my account.