I ran into a situation this past weekend. I'm a recent convert from AT&T to Verizon with the release of the iPhone 5. I was out hiking and on the drive home our fan belt broke. I had noticed during the drive that my signal strength was at 4 bars of "o" which I was surprised and excited since in this particular area with AT&T I would have had "No Service." Anyhow, when the fan belt broke, I pulled over and proceeded to send my wife a text to let her know I would be late (again, I have 4 bars of "o"), but the text would not send (not using iMessage, this is real sms). So, I gave up on texting and tried to call. The call never would go through, it would be "dead silent" and eventually would show "call failed." I was super frustrated at this point, mainly because the signal strength was so great yet I was unable to text or place a call.
Fast forward to after the hitchhiking to town, getting separate car, grabbing replacement belt (yes, next time there will be one or two or three spares in the vehicle...lesson learned), driving back, installing the new belt and driving towards town. I continued to try to text/call (I was the passenger...) and was not able to. Eventually when we were just on the outskirts of town, the signal went to "no service" then to 1 bar of "o" - (NOTE, 1 bar, not 4 bars) and I was able to place calls, text, everything. As I got closer to town, switched to "3G" then eventually "LTE" and all was well.
So, my question is whether or not you have ever experienced where you appear to have wonderful signal but are unable to place calls or send/receive sms?
Couple additional details: yes, I did hard reset the phone, airplane mode on/off, cellular data on/off, reset network settings, all that - had plenty of time on my hands...
I dragged my wife along when we decided to switch from AT&T to Verizon and she is ready to kill me for it. I promised "more bars in more places" (ironic..) and generally more happiness. It hasn't been the case. Let alone the voice+data debacle.