We could not find any description for account deletion.
Perhaps writing them a message helps (use the link).
URLS:
http://www.fedex.com
http://www.fedex.com/gb/contact/writefedex.html
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.