I frequently get spam messages sent to my iPhone messenger from email addresses. I have no idea how that is even possible. Regardless, these are always spam, and I would love to be able to block them all. Is there a way to do this?
Contact your cellular carrier to block their email to SMS gateway. I don’t think any integrate this feature into iOS but perhaps their app for managing your account lets you DIY based on which carrier you have.
You could also try this trick of adding zero numbers to your personal blocked contact list.