You should read the details of what you're agreeing to. The trial automatically extends to a paid subscription at the end of the trial period, unless you cancel it in time. If you wish to do so now, use this link:
To contact Adobe directly (this is NOT Adobe customer support):
Chat support: https://helpx.adobe.com/contact.html?rghtup=autoOpen
(make sure pop-ups are not blocked; type "Agent" to chat with a real person)
Phone support: https://helpx.adobe.com/contact/phone.html
There's no email support.
Beware of people contacting you via the forums' messaging system pretending to work for Adobe! Only those with an "Adobe Employee" tag under their name are legit. Also, Adobe will never offer to contact you via Skype, or use an email account that's not under the adobe.com domain...