Hi stephan tomlin,
You can simply uninstall your applications of Creative cloud as the trial is valid for 30 days only.
For any further issues, please refer to the following help document:
There is no need to cancel it, it is valid for 30 days & it gets deactivated automatically. I have checked the Adobe Id of yours, it does not have record of any sort of payment.
Why did Adobe force us to move into a cloud platform that nobody wanted? When did the customer stop being important to Adobe?