I receive a text message that is an email message. You can Block them by doing the same as a regular text msg.
Spam Email text comes in => Go to the top & center of the text, it will show where it came from (email address, 5 digit number or a phone number with a > sign. Press on that and it will come up with a screen with “Hide alerts, Send my location, info button. Press the info button and it will come up with a screen and at the very bottom of the screen it will say “Block or Unblock” hit the Block. That’s it. Now you can block anything that comes in.