Step 1: Go to the 'Billing History' subsection (By expanding the 'Billing' section of the left-hand menu).
Step 2: Click on 'View invoice'.
Step 3: Click on 'Manage subscription'.
Step 3: Enter the email address associated with your administrator account and click 'Send'.
Step 4: Click on the link sent to you by e-mail.
Step 5: You can cancel your various subscriptions: