What are your hub's LED's doing?
have you checked the "Check Service Status" link at the top of this page?
You can also call an automated service check line on 0800 561 0061 to see if there's an issue in the area.
If neither of the above show any issues then the best thing to do it call the service desk - it opens at 08:00 so queues are likely to be shorter at this time..