I would suggest contacting customer service if you were not able to log in.
I just got an update for an app I purchased and was able to log in and download the new version a few minutes ago.
They're not being too helpful. They say the account is blank. Since the site upgrade my login information in no longer recognized by the appstore. I have no access to the 12 to 15 apps I've downloaded from here and may need again, in particular a theme I had yet to install.
I have emailed 2 purchase confirmations I had saved that I had bought using my account so perhaps that will convince them. Dam if I'm paying another 3 bucks for a theme I'm only using cause it won't be difficult for my technically challenged mom to use when she comes to visit.