I also got a call - and I was home but didn't recognize the # so I waited to see if they would leave a message.
When they don't leave a message I usually google the # and like this one it is a duct cleaning system or some other telemarketer. I then put a call block on the # so I am not bothered again. I have also found that they use different #'s sometimes and if that is the case I just repeat my system until I find out who it is etc.
Got a call from these [***]...the man with a very thick accent asked to speak to me, I pretended I was my brother & that didn't really faze him...he went on to mumble something about carpeting or air vent cleaning or something or other, assuming I had a house. I told him my brother (me) lived in an apartment. He then shouted something in another language very angrily & hung up. I don't know where these losers get off but I'm going to ignore them!