Default GT-I9305 cm11 4.4 android unlock

hello,

I have a problem . the phone is network locked, and i`m not sure if is posible to unlock it without me going to the network operator to pay and ask to be unlocked.

i tried to unlock it but i can`t use the *#xxxx# codes as no secret/service menu show ip.
i think to downgrade from cm11 4.4 to a stock rom 4.1 but as i read here will not work and even worse will brick the phone ,

if any one know a way or have a solution for me , please reply , any advice will be tested as long as i dont brick the device

thanks, and please help me .