Tracking funds on personal accounts

I have a major problem with this Bank I have noticed for a few months they have been debiting my account on dates not set for the debit order ,after calling them I receive a notification advising my correct date of debit order being the 28th of every month however they take out the money earlier than this .If I were paying my account late or defaulting on payments i would understand however i have been advised by the call centre agent that there is a tracker application that the bank is using to track the money in my account , this is ******* and ***** .How is this bank getting away with this The last time I had a problem where the call centre agent did not advise me a date change will incur more interest and add months onto my contract now this ,Surely something needs to be in place not allowing this sort of behaviour especially after Nedbank has had a leak with personal information , If the contract says 28th do not debit peoples accounts on the 24th there is a reason for the debit date