Cancellation always takes place at the end of the contract with a fourteen-day notice period. This is necessary so that the mail carriers have enough time to terminate the forwarding order and send your mail to you again.
Your contract runs on either a monthly or annual basis, depending on which rate you have booked. You can track this information in your "Settings" under "Manage Subscription".
Your forwarding order can be terminated if you wish, regardless of whether you cancel your CAYA plan. To do this, simply go to the tab Forwarding orders under Settings and click on Cancel for the respective forwarding order.