Quote from BigFunky:
You may want to search through your emails and see if you received something like this:
Alert
18 December 2007
URGENT MATTER CONCERNING YOUR ACCOUNT
On 2007-6-14, IB delivered to you through Account Management a revised customer account agreement which our records show you have yet to access. At this time we request that you log into Account Management, accessible at www.interactivebrokers.com, at which point the revised agreement will be made available. Please note that should you fail to log into Account Management by 2007-12-31 or elect to decline this agreement your account may be subject to trading restrictions or closure.
My guess is, you missed this email, didn't log-in to accept the new service agreement, so your account was closed.
yep.. it's what i'm talking about at the beginning of this thread.