Hi @c.deskins!
I can definitely understand wanting to have your debit card saved onto your account, and it would be my pleasure to assist!
To get this added to the account, we will first need to log into your myAT&T account. Once you are on the online management screen, you are going to want to select Billing, Usage, and Payments in the upper banner. You can choose either Update Stored Payment Methods, or Add new payment method.
Sometimes a previously entered method needs to be deleted, and then re-added. This can be done by choosing the Delete option on this page. You will also see the settings for Manage AutoPay linked to the same screen.
This article is a fantastic resource for handling all of your payment requests, and also has videos and walk-throughs available.
If you have any other questions, please let us know. Have a wonderful week!
Fiona, AT&T Community Specialist