If you have not signed up for the customer portal where you can see the subscription, invoice, transaction information we strongly recommend you to do that. If you don't have the link to sign up for the portal, please submit a support request so that we can take care.
Once you have our customer portal account, you can update your credit card information on your own. If you prefer us to take your CC information and update it our side we can do that as well. Please work with your Account Manager for the same or send an email to firstname.lastname@example.org