Robo-call, which you can always tell from the initial silence while the machine ascertains if a real person or a voicemail system answers, followed by the quiet click-over to a noisy call center. Don't know who they are, don't care who they are, don't need whatever they're about.
Call every day and when I answer very rude man with an accent asks for the owner. Do not do business with a company who hires people who act like this!