Default [Q] firmware update problem sg3 sgh-t999

I just bought a phone on ebay. unlocked samsung galaxy s3 sgh-t999. It's supposed to be brand new and was in the orig. box. But the build of the firmware is ZS and in kies it says
PDA:EMC
PHONE: LK3
CSC: EMC (CHN) <- CHN I presume is China

also my android is 4.1.1 and I would like it to be at least 4.1.2 preferably 4.3

but of course OTA doesn't work because of the country code. It says registering device then processing failed.

I've tried to flash using odin but I get aboot error with some roms and in some versions as well as sbl2 error with some roms and some versions.
and my phone in download mode says it's an I747 -- the at&t model. In gs3->settings->about device it says its a sgh-t999 which is what it should be.

Kies says the firmware is up to date. arg frustrating.

Everything about this phone works except for updating the firmware.

So I asked for a replacement...which I got today. Same stupid problem, not only that, but this one isn't recognizing my cut micro sim. So if it's between the 2 I would like the original one since it recognizes the sim.

I have read that I can change the country code, but I do not want to root the phone since I want it under warranty.
what should I do to update my phone?
Thank you for any and all help