I have a paid account that has never been used to store data.  Your faq for cancelling states;

"If you are a Paid Account, first open the subscription history page, by clicking on "My account -> Subscription/unsubscription". Click on Cancel Subscription, the operate will discontinue your service immediately. Refunds are not offered for the unused portion of your service period, so we always suggest you cancel at the end of the current period, which you have already paid for. "

These instructions do not work. Please advise

Additional info:

I found a Cancel Subscription button after clicking on an order number:  The result

You have no enough storage space or download bytes to cancel, you should get the storage space and download bytes back from group members and then cancel this order!

*What* does this mean on an account that has used *0* bytes of storage and has been billed for several months...The account balance in $0.

In your case, you have a group account. You have created sub-users. In this case, you need to:

(1) Reduce your storage usage to less than 1GB;

(2) Delete all sub-users you created. You can delete sub-users from the "Group Admin" page. Logon www.drivehq.com, click on "Group Admin" link.

After you've deleted all sub-users, you should be able to cancel your group user subscription.