Sorry to hear that man.
If it makes you feel any better over here in the UK our government lost the pension records for 15,000 people. The information was put on a CD and sent, possibly unencrypted, by courier. WTF?
The info contained was: Bank account numbers, ID etc. Ridiculous.
Back to your story; you gotta watch out for ID Fraud in the future. Usually they don’t use all your information at the same time, so that you’re not aware it’s being used. You want to take that letter to the nearest police station and notify them of the possible breach of information.
That way if anyone uses your information illegally in the future you have a backup plan. I had to do that a few months ago.
eg. If they run up a tab of 10’000 dollars on your credit card in 5 years time and your bank doesn’t believe it wasn’t you, you’ll have evidence you can provide in court to defend your case.
Hope that helps.