ATT debit card

I recently discontinued my uverse subscription. As I had a credit on my account, ATT sent me a debit card. The validation site refuses to validate the card, and the two phone numbers are the card do not work. Calling the 800-288-2020 number, I get cut off each time they try to transfer me to the uverse group. Convenient, huh? I have been an ATT customer for over 20 years, but they have become so difficult to do business with. Anyone else experiencing this?