AT&T reward center website not working.

I recently signed up for att u-verse with the promise of a $300 visa gift card. I received a letter in the mail telling me to claim my reward at att.com/rewardcenter but when I go to the website an error message appears saying “We're sorry, an unhandled exception occured during the processing of your reward.
Please recheck your information and try again.” one of the main reasons I signed up for at&t u-verse was because the woman who talked me into it ensured I would receive this $300 gift card. If I am no longer going to be able to receive this gift card I would like for a customer service supervisor to contact me and let me out of my contract. I am beginning to think that this gift card is a scam to get people to sign up because many people have complained about this happening and the representatives who respond say they don’t see anything wrong with the website.