text:  Now, many legit companies offer you a chance to opt out, but you have to be careful because scammers are now using the same technique to lure you into replying stop to their messages, which will help verify that you and your number actually exist. So here's what I want you to do instead. Turn on your phone's spam filter. If you have an iPhone, go to Settings and Messages, and that's where you can switch on Filter Unknown.