There are stories of people losing 2000 pounds leaving them with only 20 pounds left in the account. Hard to believe such people could get credit cards with a 2k limit. Also if the fraudulent payments were card payments why not just reverse them in the normal way. It sounds more like bank wires.
> Hard to believe such people could get credit cards with a 2k limit
Unfortunately that's totally plausible, and infact, are the profitable customers for credit card companies. Why give a credit card to someone who can pay off their bills in full every month, when you can give someone more credit than they earn, let them spend it all, and then pay you monthly with interest?
As a point of reference, my Amex limit is 5x my monthly post-tax earnings. Back when I was only eligible for entry cards, at £250 limit increased to >£5k within a year.
It does sound like bank transfers - either SWIFT or Faster Payments. If it's a backend attack they could well have bypassed all the usual checks, including checking for positive balance & overdraft limits.
If it was a card details leak, I'd have expected cards to be cancelled, and not allowing them to continue to be used.