Q: My iPhone wont recive or send messages.

I went overseas recently and when I came back my phone would not send texts or receive them. While traveling I used the messaging system and send a few text messages then turned it on airplane mode and didn't use data internationally until I got back. I have yet to restore the iPhone because I don't have a computer right now that will back up the music, phones, and contacts that I have stored on this phone, although I think the problem can be solved without having to reset the phone to its factory settings.

When i go to settings then to messaging and turn on iMessage, a message pops up saying the following " Activation unsuccessful. turn on iMessage to try again" and also "an error occurred during activation. Try again." Also, under Send & Receive, only my apple ID is checked off and my phone number is displayed but not checked off. If you have any information that could help please advise me!