You can cancel any time. However, Service of the Applications is billed in advance on a monthly basis and is non-refundable. 

There will be no refunds or credits for partial months of service, upgrade/downgrade refunds, or refunds for months unused with an open account (rest of the month or year). Monthly plans won't be charged starting the next month. Yearly plans won't be charged starting the next year. For the purposes of equality, no exceptions will be made.

You are solely responsible for properly canceling your account. An email or phone request to cancel your account is not considered cancellation. You can cancel your account at any time from within your account site.