My iPhone 4s won't send or receive other text from people without iMessage?

When a send a text to someone without iMessage it will say "The recipient you are sending to is in your block list. You have chosen to block all texts from (and to) this recipient. Msg 2134" but I never blocked anyone and I'm trying to sign up for meetme but I'm not receiving the variation code to sign up Please Help ME!

More specific please

  • My new iphone5c won't send or receive text messages? I just got my iphone 5c shipped to me because I went to the Verizon store and ordered one. I've set up everything else… How do I set up being able to send and receive text messages?
  • My New iPhone 4 won't send or receive text messages? I have checked the service centre number which is correct, I have updated the ios software thing (I'm not too clever with Apple products but yes it's been updated).It says iMessage is waiting for activation but it has said this for ages now. I have tried absolutely everything with still nothing. I can make calls, use the internet, I can do everything else! I just can't send or receive text messages… Will someone please help me?
  • My Iphone won't receive messages but Imessage works on other devices? I can send and receive messages with Imessage on my computer but my Iphone doesn't receive any and the messages send as text messages instead when I text someone with an iPhone. I've reset it already and tried restoring it and it did't help.
  • My iPhone won't send or receive any text messages? My iPhone 4 can't receive or send any texts/iMessages. When I try to send a message it doesn't show the little red 'error' circle or anything, the text will appear and it will say sending and as it's finished loading it'll just disappear. No one receives my texts and I don't get theirs. What should I do?