I just received below from Dell after having cancelled my subscription for one of their news letters(sorry, it is Danish but the gist of it is that they assure me that all changes will be effectuated within 28 working days):
Der kan gå op til, 28 arbejdsdage, før ændringen er gennemført. I denne periode vil du muligvis stadig modtage de marketing-e-mails, som du tidligere har tilmeldt dig.
28 days? Surely you must be kidding? Who designs a subscription system so ineptly that subscriptions can only be changed with 28 days notice?