T-Mobile Is Forcibly Moving Those on Older Plans to Some of Its Newer Ones in November. Key takeaway: You can Opt-out but have to call T-Mobile Customer Care to do so. My Magenta to Go5G basic plan would cost $240 more annually for the added additional bonus of…extra hotspot data. That’s it.
I’ve been using Visible as a second SIM for the last year and I haven’t had any trouble. We were RVing so I was bouncing between T-Mobile and Visible depending on who has the better coverage.
Edit: and I can easily find people reporting the same issue on US Mobile
https://www.reddit.com/r/USMobile/comments/xya1rt/cant_make_outgoing_calls_this_number_has/
Then glad to hear you haven’t had issues!