An automated billing subscription can be cancelled via Members Area. In the "Renewal Date:" section, there is a section that says "Auto Renewal: ON". Please press the green "ON" button and you will be prompted with a confirmation screen. After it is confirmed, you will see another message and the automatic subscription will be cancelled within 24 hours (or less).
Only the payment information will be removed, your files and other settings will not be affected. You will now be able to renew your account manually by pressing the "Extend Now" button via Members Area.