We have been suspended from Twitter
We have no idea why either and have contacted Twitter through their support ticket system 3-4 times now.
For those who have entered our competition don't worry - we will be extending it depending on when our Twitter account is reactivated :-)
UPDATE: 5th Dec 2012
We're back! Only took 2 weeks! Here's our response:
Twitter has automated systems that find and remove multiple automated spam accounts in bulk. Unfortunately, it looks like your account got caught up in one of these spam groups by mistake.
I've restored your account; sorry for the inconvenience.
Please note that it may take an hour or so for your follower and following numbers to return to normal.