You can cancel your subscription for any of your displays at any time as follows:

Step 1
Click on the Account icon, then Business Settings, then Display Settings.

Step 2
Search for the display attached to the subscription you'd like to cancel, then click on it.

Step 3
Click on Display Actions, then Cancel Subscription

then confirm if you'd like to cancel the subscription.

Step 4
If you cancel the subscription, the confirmation message will be at the bottom of the screen.

Also, see How do I close my account?