To update your card details, you need to delete your existing card from the system and then re-enter your new card details. This is because Halaxy does not actually store your full credit card details for security reasons; therefore you cannot simply edit your card details without removing them entirely.
To remove your card details:
Click Settings > Payments.
In the Halaxy Credit Settings section, click the Delete (trash) icon icon next to the card you want to remove.
In the pop-up, click Yes to confirm that you want to remove the card.
RESULT: The card details are removed from the system. You can now add a new credit card in the Halaxy Credit Settings section.