Said they are a heating services company and it's time to check my furnace. Don't know them.

This is a fraud campaign currently active in Canada using a series of VOIP numbers.  The objective is to obtain your credit card number and drain your account.

If you attempt to "opt out" your number will be confirmed as live and added to a suckers list for repeated future calls.

I answered and  a machine said "good-bye".  I called back and they hung up.  I called again and answerer said they did not know who called - it is a big building.

Received call. When I answered, I heard talking & was hung up on. It appeared to be a robo-call. I called the number & asked to be removed from their call list.

No message left keep calling every day.

Call from this number, no message left