You can cancel your 7-day free trial of the annual membership through your MasterClass account by doing the following:
After logging in to your MasterClass account, open up your account settings. Settings can be found by hovering over your profile name in the top right corner and selecting 'Settings' from the drop-down menu.
Click on the button that says 'Cancel Subscription'.
Confirm that you would like to cancel by clicking on 'Cancel Free Trial'.