This person has called me twice now and when i try to call back, it's a busy line.

Just logged a complaint on the Canadian Do Not Call Registry.  If you have not already logged your phone number on the Do Not Call Registry, then this is one way to stop these types of calls.  On this same website where you register your number on the List, you can also log a complaint about a telemarketer such as this one.  I have just renewed my number on this list (it is good for a few years) AND I logged a complaint with the CRTC about this jerk.

twice today, when i call they hang up

Got called three days in a row from this same number.  When I answer there is no one there and then the line goes dead. Tried to call back to get them to stop calling.  Phone rings and rings then disconnects.

Asian sounding caller wanted to know about my security. Told him of the no call list kept insisting I was not on his list. Told him to delete me from his calls very argumentative repeating my security system. Again told him to delete me from his call list or I would report him to the national do not call list. Kept arguing about my security system. Hung up on him before telling him that I would report a complaint about him which I am just about to do. The best thing to do is to get as much information and then lodge a formal complaint as he just wants to wear you down and argue.

same number keeps calling...one time they said they did duct cleaning...other times its security systems.  In other words they just want to get into your home, learn the layout, then rob you at a later date!  B*****ds!