You can update your card anytime via the Settings tab of your Virtual Mailbox.
To update a credit card:
1. Log In to your account, navigate to the Settings tab, and click Plan & Billing Details:
2. Then click βViewβ next to Payment Methods:
3a. To update an existing payment method, click on the credit card:
3b. Click "Edit Payment method"
3c. Click "Edit Payment method"
4. Set this card as "Primary" to use for all your automatic payments. Or as "Backup" to use only when the primary payment method fails.
Your credit card should now be ready for use.