To switch from the monthly to annual membership, you must cancel your current monthly membership, then resubscribe with the annual. Login at www.allblk.tv then click MY STUFF, then Manage Account, then click Cancel Membership to complete the process of cancelling your monthly membership. Then sign back into your account and choose the annual option.
When you return to AllBLK, click MY STUFF and visit Manage Account. You should see "Annual Membership" and your new expiration date on that page.