flashed tmobile firmware on and ls980 g2.. can i fix it? please help topic

I flashed a stock 4.4.2 t-mobile firmware to my sprint ls980.. is there anyway to get any ls980 firmware back on it? i use it for tmobile which is why i flashed it but seen a few threads on how to unlock the sim and now im stuck. did i ruin the phone? or could i at least get it to work through tmobile with the firmware i flashed? i cant even get it to connect to google play. wifi works tho