Got free trial, allowed it to charge me after that monthly. Now says I have annual contract?

[digital rebel]

I used the free trial of Adobe Stock.  I kept it, allowing Adobe to charge me month-by-month.

I decided that, after this month, I am not going to need it anymore.  I looked into deactivating it and I got a message that I will have to pay over $100 to cancel it (?!)

How did I end up with an annual contract?

[Abambo]

You took an annual subscription, paid by the month. The monthly subscription, also available, does not offer a free month. What you reported now is what you agreed upon.  If you didn't use the service the second month, I suggest connecting with Adobe Customer care to see what can be done on this. 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)