How do I stop receiving spam texts?

I continue to get spam texts, always from unknown senders yet they don't end up in my unknown senders box. Maybe it's because they use email addresses, some of them inappropriate, and it has never been the same email address. I know for a fact I am not alone because the texts are 9/10 times group texts, complete with all the phone numbers of the other people they are spamming. I am given no option to report the sender and remain confused. This has never happened to me past this last week. What do I do?