How to report spam that appeared in Messages on iPhone marked "Text Message" & thus sent via carrier (e.g. AT&T) NOT Apple, & NOT from a phone #?

How do I report spam **like this**, which appeared in Messages on my iPhone? My carrier is AT&T. As I understand it, we can tell from the screen shot (because of the "Text Message") that my carrier delivered the message via SMS, not over Apple's secure iMessage protocol. Which means this is a very different situation from https://apple.stackexchange.com/questions/351754/spam-on-imessage-what-are-my-options?rq=1 . (I think the originator can have whatever email addresses they want appear both above and in the text "Text Message" - they could easily have been, and likely are, forged - the email addresses ending in .ec and .com.) I've had no success getting cooperation from AT&T. Just stonewalling and deception.  🤬 And the volume is going up.