When I phoned back, recording "this voice box is full, cannot receive more calls, please leave your name and phone number, we'll return the call." Needless to write, I did not leave that information.
... though you see "Gary Anderson" on this inbound call, as though it's a long lost classmate with good news tracking you down, nope, this is a call-bot cloaked by boiler-room telemarketers, to segment, screen or sample their new phone lists. This call bot attempts to classifies you, by how you answer (e.g., if you say "hullo?", they automatically know you're not an enterprise or business), and it loops through a percentage of a particular call list, tallying the ratio between disconnected numbers, a function of bona fide numbers --
Call center telemarketer offering free bids on home improvement projects. Blatantly ignores the National Do-Not-Call Registry and will not hang up easily.