I forgot to let everyone know the phone number for the Atlanta Office of the FBI is 404-679-9000. If you're not in Atlanta, go to: https://www.fbi.gov/contact-us/field to find the phone number for your local office. Maybe, just maybe, they'll catch a few scammers this way.
Called my cell. I don't answer numbers I don't know but then look them up online to see if legit. No message was left. Adding to block list. I'll have to remember the FBI callback idea that Ryan, from previous comment, suggested. That's excellent!