Unhappy [Q] probleme with 3g in my samsung galaxy s4 i9505

I'm living in morocco ,I have a problem with my s4 i9505 , when I use my s4 out of the capital city the 3g don't work but the s4 of my sister can use 3g.
i tryed to flash it with rom with same ap cp csc of the phone of my sister but i failed , i tryed also the flash it with many modem and rom(spain, uae, portugal,french)

spec of my s4 : ap:i9505xxufnb9
cp :i9505xxufnb9
csc i9505oxxfnb2
stock rom (portugal-tph) 4.4.2
plz help me, i know xda developers are the best one