Called, left message as follows (targeted person's name and file number redacted):
"<redacted>. This is a message for yourself. If this is not <redacted>, please disconnect now. <redacted>, this is Ms Hamilton calling with key 2 recovery. Federal and/or State law does mandate that I do inform you that this is an attempt to collect your debt. Any information obtained will be used for that purpose. You have been assigned file number <redacted> and you will need to reference that number when communicating with my office. You can reach me 8773225392."
Note: no real pause between "disconnect now." and "<redacted>, this is..."
I thought that was too much info (legally) to leave in an voicemail or on an answering machine in general.