Thank you Jennifer, for responding to my question. You've given me the best information so far. What I would like to know, however, is if the iphone 5 recipient has to subscribe to Message Blocking to block a text sent from my pc email via the ten digit @vtxt.com route or can they simply use the blocking device on their iphone 5 to block that message? If they can rely on the blocking device on their phone without using the Message Blocking service would I receive some type of notification that my text did not go through? Thank you very much for your time and for the information you sent me.