After spending about 30 minutes on chat, I've been told that they have no idea why the SIM/iPhone SE combination won't activate. I went to the XFinity store this morning, signed up for XM with an unlocked iPhone SE, was given a SIM (new line, not porting anything), and told that activation would happen in a few minutes. Got the email stating "Activation complete for (xxx) xxx-xxxx". Inserted SIM card and nothing. Still "No Service". Have rebooted. Have removed an reinserted the SIM. Have reset the network settings. Have reset the entire iPhone (and restored from backup). Have reset the iPhone and set up as new. Always get "No Service". Occasionally, I get it to say XFinity Mobile for about one second, then it turns to "No Service". It is never this difficult when I've gotten a new SIM from t-mobile, at&t, cricket, or straight talk. And those usually involved transfering service!!!
Anyone have any ideas (aside from the usual Xfinity incompetence) what I can do?