If you are having problems with your device, contact AT&T Warranty for replacement up to one year from the date it was received.
The number for warranty service is 1-800-801-1101.
Make sure you have the device in hand. They may aks for information from the device. They also have a script that they MUST follow (or so it seems) so please be patient with them. They will ask about liquid damage, etc., so expect that.