You can cancel your Timely subscription at any time. When you cancel you are able to use your account for the remainder of the period you have paid for.
After the paid period expires your account will be locked down, but your data will be retained for six months. That way you can return and pick up where you left off.
If you want your data removed and your account permanently deleted, you can choose to delete your account instead.
To cancel your subscription, go to Settings -> Subscriptions and click "Cancel my subscription".