Отмена подписки

I do not exactly understand, why you can't self-cancel. You may be in a region where you need to contact the provider.

Here are the step-by-step instruction for self cancel: Cancel your Adobe Stock membership 

If your subscription is provided by a reseller, contact that reseller for assistance.

In all cases, when you have problems, you can contact Adobe customer care, who can guide you and help you. Please note that for some language options, you have to respect the office hours. 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.

(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)