Auto-Pay is a feature that allows you to automatically replenish your account when your credit balance gets low. This feature ensures that you don't run out of credits when using our API to validate emails.
In order to use this feature, you need to make at least one purchase using the "Pay with Card"option on the "Buy Credits"screen. Then you will be able to add or delete payment methods, but only one payment method is allowed to be active.
Be sure to "Check" the Enable Automatic Payment button and click "Save Changes".