iMessage will not work after latest iOS update

Hi,

I updated my 4s on the weekend with the latest iOS update since then I have been having issues with iMessaging (worked perfectly fine before hand).

When I check Send & Receive it has my email address as the one to send from, I can't select my phone number either so when I send iMessages they come from my email address.

I have turned iMessage off & on numerous amounts of times and have managed to have my number selected (but its still greyed out) & my email address is selected as well.

I have tried unselecting the email address and sending an iMessage but it doen't work, it will only work if I have my email address selected as well.

I have tried turning off my phone & back on again & removing my sim card & putting it back in.

Nothing is working!

Yours sincerley

Very frustrated.