Phone locked in SOS Mode After Traveling from Denver to Pittsburgh

I appreciate your response, I actually spent nearly two hours at an Apple Store at the alleged Genius Bar where they assured me there was nothing wrong with the phone. This appears to be, after much research, a carrier problem, whereby any carrier can mistakenly blacklist your specific phone. The prevailing wisdom is that only that specific carrier can un-blacklist the phone. All carriers seem to honor indiscriminate blacklisting and will not intervene, even if you've never done business with the carrier who mistakenly blacklisted. I suspect. the only resolution is a class action lawsuit, which unfortunately would be treated by all carriers as a cost of doing business rather than a wake-up call.