You may cancel your subscription plan through your account on the website. You can find the option to cancel by scrolling down to the bottom of the Subscription page. Once a weekly order has been locked by the system, it can not be canceled. Canceling your subscription will cancel all (unlocked) future weeks.
If you only select to "skip" the weeks viewable in the Subscription section, it will not fully cancel your subscription. You must go to Cancel Subscription (at the bottom of the Subscription page). Please note, that if you've skipped a week the cancellation option will still be available in the next active week