It is not possible to cancel a payment in progress
Troubleshooting for when an in-game shop screen is all black or blue
Money reimbursement policy for orders of Call of Duty Points
PayPal™ can be used as a payment method on the Battle.net shop.
Troubleshooting steps for the BLZBNTGFT00000003 error
What to do if you are unable to use a payment method that you've used in the past.
Troubleshooting steps for the BLZBNTGFT00000101 error