I just received my Samsung Galaxy S4. It works great for phone, games, etc., but I had a friend call stating that she was unable to message me. I advised her that I did just recently get a new phone and that could be why. Now my brother is stating that he cannot text me either. I have tried texting my sister who also has a Samsung S4 (hers is an Active with AT&T) and did not work. I tried downloading a 3rd party application via Google Play, but nothing worked. I have also tried removing the SIM card and restarting. Lastly, I have also tried *228, but it just says that it's been activated. Any ideas? Could it be a faulty SIM card?