I installed Chainfire 3d and then It rebooted my phone and its stuck on the Galaxy siii logo... Please please please help me I really need my phone and its the i747 if that helps also before i rooted it with odin it was 4.3 :'''''(
Hi. Download firmware from Sammobile website relevant to your country and phone spec. Download Odin and flash.
Alternatively you can try Kies recovery. Enter your phone details as requested before connecting via USb. Once you see the update that is available for download connect your phone.
Btw. Did you not do a backup via the custom recovery?