NOTE: A credit cannot be deleted if it has already been applied.
Additionally, unapplied payments cannot be deleted. If removal is necessary, the only option is to process a refund internally within your organization. If a credit cannot be deleted, you can balance it out by adding a charge of the same amount to ensure the account reflects the correct balance.
Click Billing Tools > Billing Manager from the left navigation menu.
Search for and click on the account name to delete the credit.
Click on the Title of the credit to delete.
Click Delete.
To confirm, click Delete.