How do I cancel free trial for Stock? No plan appears on account and now adobe taking money from me

I don't see any Adobe Stock subscription associated with the Adobe ID you are using here on the forums. If you have more than one Adobe ID you will need to sign in with Adobe ID/email address associated with your subscription. You can manage your subscriptions here: https://account.adobe.com

The free trial is an annual subscription, with the first 30 days free and cancellable during that time. After the first month, the service will be charged at the indicated rate. You still have 14 days to cancel, and you will get a refund. Thereafter, you have an annual subscription that you can cancel anytime by paying an early termination fee of half of the remaining due. This is the standard situation.

Now to your specific case. When you took your trial, you got an e-mail, confirming the start of the trial. You can look into your account at https://account.adobe.com/plans. You can click "Manage plan" and then "Cancel" to cancel the plan. If you have trouble with this, you need to contact Adobe customer care. 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)