free trial payment

You mean Acrobat Pro?

Did you install a mobile app from Google Play or Apple Store?

If you did, you'll have to contact the appropriate vendor.  Adobe doesn't keep track of mobile app subscriptions from other vendors.

>do not remember having subscribed

>did not receive any reminder at the end of the free trial

Which is it... did you sign up for the trial, or not?

You do not receive a reminder, you agreed to a contract when you entered your financial information

When you 'click to agree' to the subscription terms while buying a subscription, that means that you really do need to read BEFORE you enter your credit card number to buy a subscription
-You also need to know that a subscription renews AUTOMATICALLY if you do not cancel during your 12th month
-there are so many people who miss the details that Nancy O'Shea added red arrows
-see the Nancy O'Shea message dated 3-22-2023 (with big red arrows) in this message
https://community.adobe.com/t5/account-payment-plan-discussions/bloated-nonsense/td-p/13669109

you'll need to contact adobe support.  there are 2 ways to contact adobe; chat and twitter:

chat:
use a browser that allows popups and cookies
and click here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human.

twitter:
tweet @AdobeCare

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true