I received 3 calls today that left the same message. It was a recording of an obscure sounding woman's voice regarding a "complaint" which butchered my name and then prompted me call back and use a code to find out the nature of said complaint.
Stupidly, I called back and received a recording that no one was available to take my call.
I'm guessing it's spam. I went ahead re-registered with the national do not call. Hopefully i don't get more calls.