It's probably your card issuer/bank (rather than Virwox) that's blocking the card, give them a call and they will reset it. In the meantime you can use Paypal on Virwox if you want, but the fees are a little more.
I called the bank this morning and explained. Reset my 2FA password again to something myself and the missus both agreed on, and they've advised that any payments would be OK now provided the password was entered correctly.
This is a Virwox thing. Let me grab a screenshot and I'll update here.
As I said, emails are unanswered.
Here ya go:
http://imgur.com/lt3AhbQ