Hello, I have an old iPhone 5 that I used for 2.5 years as my main cell phone. I've since upgraded to a 6S Plus and noticed something odd about my iPhone 5 since then: It won't receive iMessages to my cell number anymore, and I only have the option to send/receive iMessages from email addresses rather than my cell number (which is my main/preferred method of sending iMessages). When I try to toggle iMessage/FaceTime (per all the support articles/forum posts), it never works, or returns with "Activation unsuccessful." Now, I know something is wrong. Just because I switched phones doesn't mean that iMessage should cease to function at the cell number level, considering I have two non-cellular iPads that can receive iMessages from my cell number just fine. However on my old iPhone 5, there isn't even an option to choose my cell number from the list of available avenues to send/receive messages from anymore. I'm wondering if either Verizon is getting confused, or if the old SIM card in the phone is confusing it. Is this a glitch in iOS (though I have since tried doing a full wipe/rebuild of the phone from scratch with the issue still persisting), or do I have to remove the old SIM card or something?