It's rude not to email you back, but then again they don't know who you are or for sure how you got that info--all they know is that you have their sensitive data. Some lawyer probably advised them to act on the info but not communicate with you.
You've done a Good Thing, but like many good things, it will most likely go unrewarded.
You've done a Good Thing, but like many good things, it will most likely go unrewarded.