For all those who are having a problem with sending or recieving texts of any kind or even calls, I have a possible cause and fix for you. About a week ago I flew to SoCal and of course put my phone on Airplane Mode. After I took it off Airplane Mode I found that my phone no longer would send or recieve text messages. I could of course still get iMessages. I tried all the hundred and one things that Apple tells you to do and nothing worked.
Then I found an old post and tried what they said. I called my Service Provider and requested they reset the network to my phone on their end. I had to go through everything again with a lower end tech to prove I tried everything before they escalated my call to another tech who verified my information, had me turn off my phone, and then he re-set the network connections on my phone. He had me text several people and get texts back to make sure it worked. All the problems were fixed immediately.
According to the tech sometimes when the Network Connection is disconnected (ie powering off, syncing, restoring, the battery dying or putting the phone on Airplane Mode), when the connection is re-activated, it sometimes might not connect correctly on the networks end and all they have to do is re-set it.
Good luck and I hope this helps you.