3GS has signal but can not call

Question

Hello buy a 3GS, which came with iOS 4.1.2 and upgrade to 6.1.3, the issue is that I had to make jeilbreak installing cydia unable to turn it off completely because returned but had to do so because i was watching the jeilbreak is. Tetheret, worked excellent, the issue is that two weeks ago without turning off or anything, the phone displays signal light, but I can not make or receive both llamamdo with SMS the other functions work great, sometimes indicates looking sometimes no signal, and other states of course, but I can never call him again jeilbreak do nothing,

Answer 1

First checks the correct operation of the sim in another phone. 

 

regards

Answer 2

Place the sym another Nokia Mobile brand and works

Answer 3

Try a full Reset: hold down the sleep and home buttons, ignore the red Off slider, wait for the Apple logo, the let go of the buttons.