Default [Q] Gionee E3

hi. sorry for my english firs.
i bought E3 from china . When its came to me in poland i put my sim card orange and other providor. the phone cant log to network. i change rom and phone have signal but wery low and lost it fiew time in 5 minutes. in plase where my htc one s have have signal for operator about 75 % this phone have 0. In big city have edge signal in 30% and lost it all time. i have 4.2.1 android. maby you know what i can do?