With the plan, that you have taken, you have the first month free, the 11 months following are getting charged. You gave the authorization to this when you took the plan. The conditions are shown, and you explicitly need to agree to those. The confirmation e-mail does remind you of those conditions too, including the date, when the billing period starts.

at the end of the mail, you find this:

Sorry, but charge without consent does not work.
Adobe customer care can be contacted by beginning a secure chat session at https://helpx.adobe.com/contact.html?rghtup=autoOpen. Pop-up blockers need to be disabled! If the chat window fails to open, or is non-responsive, use a different device to start the interaction.
Support phone numbers may be found here: https://helpx.adobe.com/contact/phone.html. Please note that phone charges may apply.
For support via Twitter:
https://twitter.com/AdobeCare
(see also here: https://community.adobe.com/t5/creative-cloud-services/how-to-contact-adobe-support/td-p/11875703 or here
https://community.adobe.com/t5/account-payment-plan/how-to-contact-adobe-support/td-p/11843852)