I seems to have network problem with my s3. The signal just went off like that. Restarted the phone for a few times. The signal came back for about 5mins then gone again after each restart. At first the data got disonnected then the signal went totally off. But can only noticed no signal when i toggle flight mode on and off. If not, the H+ sign gone, signal bar still there but cant make calls.

How to solve this? I cant find the option to only reset network setting. I'm sure it's phone problem coz my tab can still use the same telco plan.