Doesn't look that you need to cancel the 30 days free trial. As of my understanding, you need to buy a licence after the trial to continue to use the product.
If you have specific questions concerning your contract with Adobe, I suggest you 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. If the chat window fails to open, or is non-responsive, use a different device to start the interaction.