Adobe Stock ''trial''

Nowhere is written, that after the free period of 30 days, the subscription stops. In the contrary, it clearly says that after the initial free period, you will have to pay a monthly fee.

You should contact Adobe customer care and negotiate your way out. 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)

Trials do not stop automatically, you must cancel

This space is provided by Adobe, but this is not Adobe support
Sorry, nobody here can help with an account or payment problem
This is a public forum, you need the link to Adobe support, not other users
Help Center https://helpx.adobe.com/support.html is a good place to start
Be sure to remain signed in with your Adobe ID before accessing the link below
Do be aware that Adobe's staffing is impacted by the virus, so wait times are long
-you MUST make sure that your browser does NOT block ads, scripts, or pop-ups
-you MUST also allow 'cookies' in your web browser for the link to work
This link will go directly to the chat option
Type "Agent" in the chat box to bypass the chatbot and be connected to a person
-Meaning type in the word Agent without the quote " " marks
https://helpx.adobe.com/contact.html?rghtup=autoOpen
- or by telephone https://helpx.adobe.com/contact/phone.html
.
Adobe does NOT do support by email, so beware of answering anyone who sends you a private message
-click for more information about scammers https://tinyurl.com/10791730