outgoing and incoming is disturbed in Galaxy S3

[Ad Tabassum]

hi seniors,
I have galaxy s3 SGH-T999 of t mobiles. I am much worry because in a specific area neither can I make a call nor others can call me, no sooner i touch the boundary of that city {Bahawalpur} i face this issue. phone works well in other cities, even when i leave the city area phone works well but in the city i cant make a call nor others can contact me, please help me out. Sim works well in other phones.

 

[Golfdriver97]

Welcome to the forums.
Have you tried the same sim card in a different S3?