I want to cancel my subscription immediately and cannot figure out how to do this.
Contact Adobe. Warning, scammers may contact you privately pretending to be Adobe staff. Adobe will never send you a private message asking you to email an account that isn't @adobe.com, or use Skype. Adobe never ask you for their password. These scammers want your Adobe info, credit cards, your money and control of your computer, please take care.
I don't see any Adobe Stock subscriptions associated with the Adobe ID you are using here on the forums. Is it possible you used a different email address when you set up your subscription? If you did you would be able to log into https://account.adobe.com to cancel your subscription.
If you require additional assistance please contact customer care, https://helpx.adobe.com/contact.html. Click on the chat icon in the lower right portion of the page. If you are unable to see this feature you may need to scroll down before it will appear or set your browser to private or incognito mode.