Seems that you're from the Netherlands or from Belgium. Are such "wrong" charges really an issue there? In Austria I would just let my bank cancel those charge

Seems that you're from the Netherlands or from Belgium. Are such "wrong" charges really an issue there? In Austria I would just let my bank cancel those charges (you can do this for free) if they are not justified. As far as I know, going below "0" wouldn't be a problem either, because the bank then retroactively "recalculates" your account history without the charges in question.