I want to cancel the subscription

first, understand that if you're canceling after the 14 day cancellation period, you'll be subject to a cancellation fee (=1/2 the remaining cost).

here's that info in adobe legalese, https://helpx.adobe.com/uk/manage-account/using/creative-cloud-subscription-terms.html#cancel

that said, if you still want to cancel here's how - http://helpx.adobe.com/x-productkb/policy-pricing/return-cancel-or-change-order.html 

if that cancel help doesn't help you cancel, use a browser that allows popups and cookies and contact adobe support by clicking here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true.

p.p.s you can also use phone (but chat is usually quicker), https://helpx.adobe.com/contact/phone.html

p.p.p.s. you can also use twitter to tweet @AdobeCare.