How about in the cases that they have personal info in sms messages or voicemail? Info got picked up from somewhere?
It's just an old password found in a breach years ago, they don't have anything else that's real. The difference here is that if they call and leave a voicemail with personal info, go to the police. They're not gonna bother tracking down a social engineering email, but they may be more inclined to go after verbal blackmail.