Sorry I think perhaps there has bee some misunderstanding of the problem. There is nothing to log into no interface no way to change the password. It is not blocked but completely absent and replaced by this statement:
Your mailbox is not available at the moment.
Please retry again in one hour and make sure you are using the correct password to access your email from all of your devices.
If the problem continues, please call our team for help on 150 from a Virgin Media phone or mobile, or 0345 454 1111 from any other phone and select option 2. For details about how much it costs to call our team from a Virgin Media home phone, visit virginmedia.com/callcosts. Call costs from other networks and mobiles vary.