mobile

Hi guys, so i had a custom rom on my s4 i9505 and after month i decided to go back on my original software and remove root, downloaded the firmware for switzerland swiscom and after i tried to instal it via Odin it just fail every time, and now i cant turn on phone, it says firmware upgrade encountered an issue please select recovery mode in kies and try again, spent a lot time on forums, but i am pretty new in this world so didnt help me so much. Originaliy had kitkat i9505xxugnh7, now can someone tel me how to fix it, step by step, what i need to download and...?I would be very grateful..
p.s. sorry for my bad english, not my first language.