I forgot to cancel my account and I don't want to pay the cancellation fee

You may also contact Adobe Custome Support via Phone :

https://helpx.adobe.com/contact/phone.html

You can still try contacting customer service to see if you can cancel without the penalty, especially if you are within 14 days of the start of the subscription.

Be aware that because of the pandemic, wait times are far longer than usual due to reduced staff and higher demand. Please be patient with the people to whom you speak. Like you, they are feeling a great deal of stress. A little patience and understanding will go a long way to helping you in your particular situation.

Adobe asks for payment information when you sign up for the trial, which should be a pretty big clue that if you don't cancel you'll be charged. There is also a link on the sign-up page that explains their terms and conditions, including the cancellation policy and a warning that if you continue you've accepted those terms. 

check https://helpx.adobe.com/creative-cloud/help/cancel-membership.html
p.s. if you're cancelling an annual plan early, there's a penalty (=1/2 the cost of the remaining months).

if the above link doesn't help you cancel, using a browser that allows popups and cookies, contact adobe support during pst business hours by clicking here and, when available, click 'chat', http://helpx.adobe.com/x-productkb/global/service-ccm.html