unknown caller

why am i being called by this number and a person says nothing and will hang up if i ask them a question

i am on the do not call list, they keep on calling, i am reporting this to the crtc..

Air Duct Cleaning Services calls every other day. Been getting these calls for months. Finally got fed up and booked for them to come. Gonna take photos of their licence plates and get some sort of documentation. Going after these b*****ds myself 'cause the CRTC and BBB are USELESS!!!!!

And when you call back it says to enter an extension number

Harssing telemarketer phone calls  !   We have to stop these creeps !