on the letter they responsed

on the letter they responsed to us said "this account was hearby sold, assigned, transferred and set over unto ***, Inc. with full power and authority to do and perform all acts necessary for the collection, settlement..."
and on the bottom of the letter there is an "official seal" . How did they get all the information? We just moved, how did they get our new address and new phone number if this happened 12 years ago.
On the phone they keep asking my hu*****and " is this ***-***-**** your SSN?" my hu*****and responsed not giving any information out on the phone when he doesn't know who they are.
Should we pull out the credit report ourselves again check if what they said is true? I am just thinking if this is true wether this bad mark would be still on it since it is more than 10years old. I read the credit report before, it said bad mark only stay on it for 7 years, even bank ruptcy only stay for 10 years.
Thanks for all the help.