Could not activate iPhone (ios 7)

My iPhone 4s suddenly wants activated - when unlocked, it shows me my wallpaper. After sliding to unlock, it asks for my passcode. When I enter it, it takes me straight to the 'Activate iPhone' page - like it wants to be set up.

The text on the page:

"This iPhone is currently linked to an Apple ID (example@example.com). Sign in with the Apple ID that was used to set up this iPhone."

After I input the correct credentials and press Next in the top right corner, the title of the page changes to 'Activating...', then changes back to how it was before.

About 15 seconds later, it transitions to a 'Could not activate iPhone' page:

"Your iPhone could not be activated because the activation server is temporarily unavailable. Try connecting your iPhone to iTunes to activate it, or try again in a couple of minutes.

If this problem persists, contact Apple Support at apple.com/support"

I've tried to contact Apple chat support also, but it is not available of course -.-!!! And I can't call apple support cause' my freakin' phone won't activate......