Spoofed # as they are calling from a duct cleaning call center. Most likely in Pakistani. Told them I don't have ducts but different numbers call us all the time! DNCL in Canada won't stop these calls!    

Name = "unknown" .... Duct cleaning service ..... hung up.

Canadian company telemarketing for duct cleaning. Keep calling. I'm on the do not call list

Some licensed phone company within North America has control of this number and is permitting it to be used fraudulently.

Where are the regulators?

Ask for me with my full name.  Claimed to be Dell Technical support and said my computer is infected as their "server" flagged for suspicious traffic.

The whole scenario is odd and I told them my computer is perfectly fine and asked how did they track it. Then he hanged up.

Probably a scammer or a phisher. Or someone who wants to sell antivirus software. Don't be fooled. Dell won't call you even if you computer gets infected.