It's not very likely to be a person, it's a hacking of the website problem and a2b keep saying their site is secure.
I'm not sure ultimately who ends up paying what, the banks retrieve the money from the likes of O2 , not sure where O2 then recover their money from though.
I'm just so glad to have a new card at last, a pain without it,
I need to book 2 transfers and just don't want to risk it again, been holding back hoping would be resolved and sad to read its still happening.