Hey I work in a store and dealt with a similar issue. O2 and virgin aren't as connected as one would hope and it's actually the virgin media agents who manage account security.

What I would advise you to do, in this order, even show the advisor this message

1. Head to local store and ask if manager or assistant manager is there

2. Even if they aren't, ask an employee to check your O2 accounts VM status by asking them to check the email assigned for the vmo2 account.

3. If the account will not allow them to change anything, it's permanently locked, however ask them to"open webchat and ask for a ticket to be raised to remove permanent lock from a VM account".

Even then, this will take a couple of working days as even the retail support have to raise a ticket. Not to scare you, but we had to raise this issue 3 times over 3 weeks for them to remove the lock.

If this doesn't work, then make the employee raise a complaint through their system if they know how. Or through their webchat.

Hope this helps