They also call from 417 800-2511.  Same scam - different number.  

This time they called themselves Research Study.

Buy a call-blocking phone.  Uniden and Panasonic make wonderful call blocking phones and they're inexpensive.  They also come with at least one wireless handset.  Very handy!!!
These phones also block “Out of Area” and “Private” calls.

Plays recorded message from another machine with multiple numbers and multiple attempts. After I hang up it calls back, rings once and then hangs up.

This message sounds like spam

Same as some of the other comments here; spam call about changing meds for COPD

Called and left no message