Most likely the dodgy 'energy efficiency' company Aussie Green marks, they installed dodgy mismatched breather seals, and cheap showerheads, then charge the government much more than they are worth. They call the day after installation (they arrive at your doorstep without prior notice). I missed the call, and no message was left.

Caller: Energy efficiency company

Energy efficiency company returning my online enquiry about free draught-proofing products

2nd day in a row this number has called and left no message. Unable to find this number as being for any business.

Let it go to voicemail, no message left.