You should contact Vistaprint asking for account deletion (mail or telephone). You could use the link provided. Send an email (subject: Account – as if we need to tell you this, you’re no kid anymore eh?) and request deletion.
URLS:
http://www.vistaprint.com
http://www.vistaprint.com/customer-care/contact-us.aspx
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.