Sorry GS. At least it was taken care of quickly.
Worst thing about this is that once your info is out there you may find it used more often. I think I've had about one instance of fraud every year for over a decade: cabinets bought, car loans opened, Walmart charges, money directly out of my bank account.
There is really no way to know how they got your info, unless you can find them and ask them nicely whilst you rip their arms from their sockets :)