1) Go to your account page and log in: https://www.idrive.com/idrive/home/account.html
2) Click the drop-down arrow next to your account name in the top-right corner.
3) Click on "Account" at the to of the page towards the left side.
4) Click "view" to the right of Billing Information.
5) Click "Disable auto-renewal" at the bottom of the page.
6) Verify that the screenshot attached to this post pops up on your screen, then click "Stay with iDrive". (I would do screenshots along the way just to have a record -- just in case). Hit "close" next to the Billing Information section, then "view" it again. It should show half the renewal price now. Screenshot it to be safe.
I did this on 2 different accounts.