Here's a fun thing to do, since they won't stop calling - when they ask how many bedrooms your house has, say something outrageous like "27" - they have no idea how to respond and they'll hang up on you. It's still a waste of your time but more fun - and it took them more than a week to call me again.   I have reported them to CRTC but not confident that the calls will stop.

Don't worry if you missed the call - they'll call again, and again, and again......even after you've told them not to. They claim to be an air duct cleaning company and they're extremely annoying. When you question them, they'll hang up on you, they've done it to me several times.