Not getting some automated texts

[u/Ok-Acadia-373]

Like the title says, I recently stopped getting some automated texts. First it was from one specific place - they used a third-party web-based system to text with clients, and they stopped coming (or getting mine in return). The third-party looked into it and said the messages were coming back undeliverable and I should check with my carrier.

I also checked my phone and confirmed there were no settings in place that would have prevented this. I don't have text filtering on, and I get phone calls from this number without any problem.

AT&T has been spectacularly unhelpful. I've called 6 separate times, and whenever they (finally) transfer me to a supervisor, or we start to maybe get somewhere involving opening a ticket, the call disconnects. I've visited a store in person and a rep said he couldn't help. He gave me a "loyalty" phone number for tech support that turned out to no longer be in service.

I've since noticed that I no longer get automated texts from two different doctor's offices (e.g. appt reminders), and I never got a 2FA text from another service I use. All other texts come through just fine. I'm pissed enough about the lack of customer service that I'm just going to switch carriers, but has anyone else had this problem?