FTP pokerstars .co.uk/.com Accounts?

I tried to register at Pokerstars to be told I couldnt as my username was being used on FTP.com(by me!)

I asked pokerstars for password reset as FTP wouldn't let me log in and was told the account exists, but I would have to reregister on .uk (certain I already had!) but sharkscope says lilmishap(FT) is closed?
So are we not allowed to use the same username on both sites as that seems daft!

Also a lot of the usernames have (closed) beside them so what has happened at FT? How do I find out if i have an account there or not, as the site doesn't seem to be closed?

I'm lost