Probably neither. Usually in any warranty situation with At&t, you are going to contact the carrier directly. It is most likely out of Amazon's return/exchange window, and even if you did contact Samsung and were willing to replace it, they would go through the long process of sending you a phone, then you send yours back. Recently, someone in my family had a warranty situation with another At&t smartphone; we contacted customer care, and were later transferred to the warranty center. They were helpful, and deemed that the device was in fact defective and all we had to do was bring it in to a local At&t device support center. There, they pretty much just swapped out the defective phone for a new(refurbished) one. Not sure if they have that kind of "device service center" in your area, but if they do, its definitely worth avoiding the hassle of waiting 7-10 business days for a phone. Hope this helps, and hope your problem gets fixed.