trentsc

I'm having problems with my new S3 on T-Mobile. It keeps losing its mobile signal, but I only find out when I try to send someone a text message or make a call and I get the following error message:

No network Connection
No signal found for mobile networks

A quick reboot sorts the problem, at which point the SMS I was trying to send gets sent and I receive a wash of incoming messages that have obviously been sitting in a queue somewhere.

I've tried going into Settings > More Settings > Mobile Networks > Network Operators and I'm offered several providers, including two EE entries. Whichever I select tends to sort the problem, but it recurs later, and this seems to be a daily occurrence.

Any ideas? As the phone was provided by T-Mobile, I'm guessing that it's locked to them/EE...

Thanks in advance.