I tried to upgrade to a Samsung GS3 & got a "could not contact carrier to verify eligibility" message. I talked to an Amazon rep - he said it's a known issue, try again in a few days.
After a couple of days with the same result I called Amazon again - this time was told to remove the PIN code from my AT&T account. Did that & the upgrade went thru. $10 with a 2-year contract! Amazon also upgraded to over-night shipping to make up for the delay.
FYI
PS - an AT&T rep is needed to take the PIN off then add it back after the Amazon order goes thru
After a couple of days with the same result I called Amazon again - this time was told to remove the PIN code from my AT&T account. Did that & the upgrade went thru. $10 with a 2-year contract! Amazon also upgraded to over-night shipping to make up for the delay.
FYI
PS - an AT&T rep is needed to take the PIN off then add it back after the Amazon order goes thru