********* advertising

I receive at least one email advert a day from Zando. With so many retailers constantly sending promotional emails, it just gets too much. For the past few days I am constantly requesting Zando to unsubscribe me, but they completely ignore me. Is there not some sort of advertising standard or rules of ethics that they should follow? May this be a warning to all of us not to quickly make our email address available to such online businesses. Out of principle, my business will go elsewhere.