I want to share my experience going from AT&T to Spectrum Mobile. Just so you know - I am completely happy with Spectrum Mobile. I just didn't know what to expect, so here is what happened.
I called Spectrum Mobile and said I wanted to overlap the accounts until I was sure I was ready to pull the plug. Spectrum Mobile Sales assured me I could pop the sim cards in and out to go back and forth between services. Not true. Read on...
I went ahead and ordered the new sim card (chip?) from Spectrum and received it four days later.
I followed the instructions and went online to port the number (the Spectrum Mobile Sales Guy assured me repeatedly that there would be no such step and all I had to do was insert the new sim).
Hit my first glitch. The online portal rejected my AT&T account number and would not let me proceed.
I called Spectrum Mobile's Support Line. They (she) answered right away. I had previously tried twice to call AT&T support and hung up after being on hold for over 45 minutes. Spectrum Mobile's Support was awesome. She was friendly and very knowledgeable. She explained that some AT&T accounts used a variant U-Verse format. Anyhow she ported the number and the phone immediately went dead as she said it would.
I put the new sim in my iPhone X .....and......everything was perfect. Contacts lists, old messages, emails, music, settings, networks, you name it. I never had a single problem.
But then some unexpected things happened.....
I got security warnings from my bank and several other places, including Facebook and LinkedIN that my number was invalid. I thought for sure I had been hacked. Apparently they not only know your phone number, they know your service provider! In each case it was easy to confirm that i had just switched carriers. Couldn't someone have warned me?
Then I tried to log in to AT&T a few days later because I was very happy with the new Spectrum Mobile and could not see any reason for switching back. I could not login. AT&T immediately cancels your account when your number is ported. Of course I didn't care, but again, couldn't someone have warned me? Oh, and so much for the nonsense of being able to switch back and forth by simply changing the sim card!
I find it really strange that for all the people I spoke to, and all the research I did online, not one thing, nor one person actually knew what was going, except for that one support girl at Spectrum Mobile. Thank you Miss Whoever you Are.
It is now a month later and I couldn't be happier with the service, the wifi calling, the personal hotspot, the web site, the mobile app, and of course, the support. And I am saving at least $70 a month!