spam emails to text messages

For the past year or so I have received text messages from gmail, or VZWpix.com accounts. There are always the same 20 people with actual phone numbers on this group. I have blocked every time, but somehow I still get them. There is no way to leave the group because the original text message is always being sent from an email. I have research multiple forums, but everything that is being said to do, I don't have those options. I have filter unknown senders on as well and still receive them. It is getting really annoying. All of them refer to some sort of sexual content. I have an Iphone 8 plus if that matters.