Scammers. Won't leave a message - they want to get their hooks into a live person. Call the number and immediately goes to a recording, "Press '1' to be removed from our list." What legitimate business won't allow you to reach them?
Called the number back and it said "Press 9 to be placed on the Do-not-call list. It make take up to 72 hours for the change to provocate through our system." Here is the definition of Provocate:
Full Definition of PROVOCATION. 1 : the act of provoking : incitement. 2 : something that provokes, arouses, or stimulates.
I think they are looking to act on my part to collect bad debt for my company.