Caller ID says "3397077549" (The default format is (xxx) xxx xxxx; so they spoofed the caller ID to look vanilla but have failed). They leave no message.
I call back after business hours (using *67 to block my number). Their outgoing message is, "Hello, you've reached MDS communications. We're a telephone fundraising company that specializes in calling for nationally recognized charities, non-profit organizations, and political committees. Please, accept our apology if you do not wish to be called particularly if you have signed up for the national do-not-call list. As you already know fundraising calls are exempt from national do-not-call lists, and many people who have signed up in order to block commercial calls still like getting calls from their favorite charities. If you'd like to receive a call back from us, please, press 1. If you'd like to be added to our do-not-call list, please, press 2." ( I never do the do-not-call list as it can actually make things worse).
Likely they are what they say they are, someone calling for a charity or a political campaign.
I called the # back it is a "charity" line so it is exempt from the do not call list. If you listen to the entire message there is a way to opt of of them call, hope it works.