I have a 3GS which has just started having issues with 3G connection. It refuses to receive SMS messages, but I am able to send them. I have tried to reset network settings, turn off iMessage, restart numerous times to no avail. The only way I can make it work is to turn off 3G, turn the phone off and on which allows SMS to be received.
Am I missing something obvious as to why it's having a mini meltdown?