For the past hour my iPhone 4S running iOS 6 has been trying to find a network. It is just staying on "Searching..." I am in my house which almost always has four bar Optus 3G reception. I have now realized that the "Carrier" option in Settings is gone/missing. I have tried restarting the whole phone, resetting the network settings and taking out the SIM and re inserting it. All with no luck. Any suggestions?