A few weeks ago, my iPhone 5 quit making or receiving calls. I tried an assortment of maneuvers to get it to work but all of them failed. All of the other aspects of the phone worked, I simply did not have any “bars”. I finally saw a segment on the news that stated the problem was the result of a glitch in the operating system. And the way to fix it was to remove the operating system and reinstall it. So, I gave it a try and sure enough, it worked. Well, that saved my a chunk of money.