S3 - suddenly Mobile network not available
I have a Samsung S3 GT 19300.
Purchased in Hong Kong. Using China Unicom, and I have a monthly plan, fully paid up.
It is stock - I have not rooted it.
Suddenly, about 3 days ago, I started having problems with it connecting to the network. I ignored this issues because I was on vacation, and roaming ... so I thought it was due to the roaming.
I'm back home now, and I can not make any calls.
When I call out, the phone:
- sometimes doesn't connect to the network - the call doesn't go through at all
- sometimes dials the other end, but there is no sound between the two phones. When that happens, the phone connection lasts about 15 seconds, and then the Samsung phone shows the network as not available, with the circle with a slash through it, and says "Mobile
network not available".
I've rebooted many times.
I've took out the SIM card, and put it back in.
I've checked the firmware - and the firmware is current.
I've disabled JuiceDefender Ultimate
Strangely, I CAN send data thru the network, but can not receive or make calls.
I also found out that WHILE I CAN SEND / RECEIVE data (internet), FourSquare can not identify where I am...