iPhone stops making calls (bad sim card)
Ok, so you’re in Kansas City for a bachelor party and suddenly your iPhone stops sending or receiving calls. It’s Friday night so you’ve only got a day to get it fixed because a certain entertainer (ahem) will be calling you on Saturday to confirm the location of the party.
Like any normal bloke you figure, not a problem, right? You go through the usual rigmarole of resetting your phone, resetting your settings, removing your sim card, putting it back in, etc. After a few hours of frustration you call your carrier and explain the problem. They have you repeat the above and eventually instruct you to contact Apple.
If your carrier is AT&T, this may be a reasonable next step. If, however, you’re one of those shameful people that’s unlocked your iPhone for, say, T-Mobile, then you’re starting to get concerned that tomorrow’s festivities are at risk.
Fortunately for you, one of us recently had this very thing happen to us. Like you, we burned a significant number of hours trying to figure out just what was wrong with our iPhone.
After the above steps we scoured the web looking for a clue to our issue. This netted us little luck and we were left to figure it out on our own. Now that we’ve gone through this exercise we felt it important to post the solution here so future groomsmen (or bridesmaids) could avoid disaster.
Let’s show you what the iPhone looks like should you encounter this problem:

iPhone not displaying carrier
As you can see, the carrier isn’t appearing even though the phone is showing signal. During our search for the answer to this problem we even had someone suggest that our phone had magically re-locked itself for T-Mobile.
After much trial and error we eventually had the idea to switch out the sim card.
Voila! Problem solved.