Problem flashing, rooting in many ways

I had problems with my phone so i put the firmware back before sending it to the maintenance,
now that i have my phone back i tried rooting in every single way i found on xda, they all execute pretty well, but once i try to confirm if its rooted, it is not.
Then i tried to put a kit kat firmware, cuz maybe it was easier to root that way and the flash tool doesnt work.

What to do, guys?