There are two ways to update the credit card stored on your account-either by phone or online. If you're wanting to update it online, login to the billing portal at http://www.hfcbilling.com.
If you have a credit card on file already, simply login to the billing portal and scroll down to the bottom on the Home page. You can then click Edit on the existing credit card to enter new credit card details and an address.
If you do not have a credit card already on file, you have to have an open invoice in order to add a credit card to your account. From the Home page, click Pay Now, enter your credit card details.
Before you submit payment, make sure the checkbox at the bottom is checked to allow us to use the credit card for future transactions.
Here's a video that walks you through these steps as well.