If your default payment method used for Instant Checkout fails, but books were still instantly added to your account, payment will be required before being able to make a new purchase. Click the "update your payment information" link in the red banner at the top of our site. You'll then be taken to the billing page where you will be able to update the payment method on file or change to a different credit card, PayPal, or Pay with Amazon method.
Your cart page will list any past purchases needing payment separately from new items in your cart. Upon checking out, you will see the total payment required for past and (if applicable) new books.
If you have any questions, feel free to email us at firstname.lastname@example.org