Be logged in on the site; use the deletion link. Scroll down a bit and go for Kundenkonto löschen, that should do the job.
URLS:
https://dailydeal.de/
https://dailydeal.de/customer/account/edit/
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.