If you cancel your subscription, you will still have access to your Premium subscription until the end of the paid period. Once the paid period is over, your Premium account will become inactive.
You can see if you have a recurring subscription by viewing your Account Summary page [http://www.filefactory.com/account/]. Hovering over the area will show your next payment date.
To cancel your recurring payment, click the "Recurring Payment" link or navigate to Products > Billing History [http://www.filefactory.com/account/services/billing.php].
You will see a list of current recurring payments if you have any. Just click the 'Cancel' link to stop a rebill from occurring again.
You will still be able to use your Premium account until it expires, but you will not be charged again.
Note: if there is no Cancel link, it means that either your recurring billing has already been cancelled, or that your account does not automatically renew, so no further action needs to be taken.