I was visiting my sister a few days after the iPhone 5 came out. I have an iPhone 5 from Verizon and she has an iPhone 5 from AT&T. I decided to pop her AT&T nano SIM into my Verizon iPhone to verify the unlock. Sure enough my phone displayed AT&T service and I was able to make call using her number. While I was playing around, (looking at the field test menu whatnot, she pug my Verizon nano-SIM card into her AT&T iPhone. Naturally it didn't work. She said that it said something about only supported SIM cards could be used in the phone. So whatever, we swapped the cards and were done with it. Now, my Verizon iPhone is on my business account. I happen to be the manager of the account for my company as well. I signed into Verizon's Mybiz site and pulled up my line to make a change to the text plan, and noticed that it no longer showed my device as the device on the line. It showed a generic phone photo, and for the device ID it showed a device ID that didn't match mine. I was suspicious so I asked my sister for her AT&T iPhone's MEID. Strange. Also, Mybiz wouldn't let me change my plan or features. I went through Mybiz's update device process, putting in my Verizon iPhone's actual MEID. The process goes through, but it never actually updates. The page continues to display the AT&T iPhone's MEID. I tried again, no luck. Still can't change any features on the line either. I called Verizon support and they tried to update it in their system, but they said after the processed it, the MEID would keep reverting to the AT&T iPhone MEID. They said they would look into this. I talked to them yesterday asking for an update, but they said they cannot figure it out. Keep in mind, my phone is working fine. Voice, data, and texts work. However I am unable to change any features on the line. So, has anyone here done the same thing? Accidentally placed a Verizon nano SIM into an AT&T iPhone 5? If so, did you have the same issue, and were you able to fix it? I was thinking perhaps I'll pick up a replacement nano SIM tomorrow and try that, but figured I'd check with the community first. Thanks.