I can't send text messages but imessage works fine?

I have an iPhone 5 and it's currently on 7.0.4. I have this bug that annoys me a lot. I can send messages via iMessage but not via Text Message. I found out that it for some reason was turned to off but it still won't send text messages after i turned it on. It really makes me angry and i would just like to know if any of you know how to fix this? :/

The best and easiest way to fix these problems are: open the toilet seat, stretch out your hand (with the iphone in it) drop it in the toilet and flush. Then you go to the store and buy android