Click on My Subscription and then click the blue Cancel button.  It will immediately cancel your membership and you will not be charged the one-time fee of $1.  You will no longer have access to the course content once you cancel your membership.

It means you are still in your 7-day trial period, so you have not been charged the $1 yet.  When you click on View it will show you how many days you have left on the trial.  At the end of 7 days, you will be charged the $1 and your order will show Completed.