421 4.2.0 sender rejected AUP#SNDR

I'm seriously thinking about it. I've spent numerous hours with support on this. And even if they do fix the problem, I've noted that since sometime maybe around late March, my messages would be randomly delayed, sometimes over 24 hours.

It's sad, because my first cell phone was with T-Mobile, and I remember back then the support was excellent - a gold standard by which I've judged subsequent support experiences… I ended up moving to Sprint a long time ago for their "Unlimited Everything" plan.  I'd noted that the support with Sprint wasn't that great, but now that it's back to T-Mobile, it's *loads* worse.

Honestly, the path of least resistance is to switch my notifications to discord, but that just seems wrong. I *pay* for messaging and I'm supposed to get "support" if it's not working, so I feel like changing providers simply out of disgust for what they're putting me through. I get that the merging of networks is rough, so I'm trying to be tolerant, but if they're not going to the effort to make the transition smooth for their customers, then it does not speak well for them.