If you need to change the credit card you use for the site, follow the directions below.
First, log in to the site and click the drop-down arrow next to your profile pic in the upper right corner.
You will see an option for Wallet.
When the Wallet page opens, look for the Add New Card link in the lower left-hand corner.
After clicking the add new card link fill in your new Card's information and click Add Card.
Set the new Card as your default card.
Now remove your old Card by clicking the down arrow next to the Card and clicking Remove Card.
