Usual duct cleaning calls from an out of service number. Next call I get from these duct cleaning A**holes are going to get a  high decibal ear piercing blast from a sounding device.

This number has been calling our home phone multiple times. Finally picked up on the call, person says hello. I say "Can I help you?" Next thing you know, the person has already hung up. I call the number back and the line "is not in service." How convenient. A***oles.

This is the infamous "Duct Cleaning Company", I get at least 2 calls per week.
Sounds like an Indian telemarketer, they won't take you off their list.

I can't get any company info off them, they hang up when they realize I'm not going to give them my credit card info.
The phone companies allow this kind of crap most likely because it generates a crap load of revenue for them.

Received call and picked up but did not say anything with call eventually being disconnected. I called back and the recording said the number is not in service ??  You think these idiots would have something better to do with their time !! Reported it to Bell and they got the same recording and will forward to their appropriate department for investigation.