tried to update my Samsung Galaxy S3 and screwed up the phone need help

[Android Question]

I have a At&t Samsung Galaxy SIII its unlocked and the model number is an SGH-i747m I just wanted to update the firmware to the newest update but I failed. What i did first was I started up Odin and put the phone in Odin mode (hold power+volume down + home button) then I pushed the volume button up and selected a i9300 update which failed it did not go through ( I found out this is not even the correct update for my phone). Then I wanted to restore the phone its factory settings because I kept getting notified that the firmware did not update to connect to Kies but kies will not recover the phone. It asks me for a recovery code from the other PC but I never did any sort of thing on another computer. I don't know how to get my phone back the Samsung opening will come on but will turn off right after. Im so frustrated I just do know what else I can do to save my phone can anyone help me. And my level of flashing a phone and stuff and putting a new update to a phone this is the first time doing this so I really dont know what the heck im doing can anyone help me out, thanks.

Phone specs:
Model:SGH-i747m
S/N: R21C64A1SYJ

 

[girolez]

Hi and Welcome

That's not good. You tried to install a rom meant for a different device. You may have written it off - but maybe not!

Suggest you try looking at this

[SAMSUNG GALAXY S3 UNIFIED TOOLKIT V7.0] Drivers, Backup, Root, Recovery + MORE [GSM] - xda-developers

It probably seems complicated but it is necessary to understand what you are doing. This toolkit will guide you through most of the possible actions. I also suggest you register on the forums and ask for help in the s3 all things root forum where someone will be able to have a 2 way discussion with you.

Good luck

Roger