After a week of downtime, things are back up and running. I can't explain why it takes so long to close a Google Apps acount (5 days advertised, but took longer), but I'm happy things are back up and running (for one, this domain is used for as my OpenID identifier and I couldn't login to many services!).
Thanks to Google for finally sorting it - but should it really be this difficult? There's definitely some room for improvement...