Impersonating officials
Someone pausing as a debt collector or IRS agent might contact you with an urgent message about money you owe. Another approach is to claim they have money that is owed you and all they need is your bank account information so they can send it to you.
In either case, contacts like these are almost always fraudulent. Legitimate contacts about matters like this are generally made first in writing, and that should allow you to verify the addresses being given and get help dealing with the matter.