Account credit
Account credit is issued or applied by Billing; it is not a public checkout payment method.
Account credit can exist when Billing issues a credit or applies an approved adjustment. It is not currently presented as a general customer payment method during public checkout.
Review credit notes and invoice adjustments in your account. Contact Billing from the account email if a promised credit is missing or should be applied to an eligible unpaid invoice.
Still stuck? Open a ticket or use live chat.