Why are they blocked?
Long ago Vircurex was supposedly hacked and all it's bitcoins stolen. they 'solved' the problem of paying back accounts and still staying open for business by placing all affected accounts in a special 'frozen' balance. You can see it but not withdraw it. :/ The amount still shows up when you login, under 'frozen funds' -which they are paying back slowly over time. -You never know when they'll pay back your account in particular, it's a "top-down, bottom-up" strategy according that could take weeks -or years.
Only for those with faith in Vircurex, but a chance to profit if you're a believer in them and don't mind waiting. -I don't have the time anymore.
reference link;
https://vircurex.com/welcome/ann_reserved.html