iPhone 5s, full reset, now won't activate due to activation server being temporarily unavailable

Did "erase all content and settings" on my iPhone 5s yesterday, due to signal being extremely intermittent, came to try starting it up again, with the view of just putting everything straight back on from iCloud, and it wont activate, been trying for 12 hours now, and just says "Your iPhone could not be activated because the activation server is temporarily unavailable"
I have tried numerous times over different WiFi networks, and also by connecting to iTunes... any help.. at all?