I, too, have received these "Dell" tech support calls and angrily yell at them as I hang up within 15seconds.
Lately though, I received a bombardment of calls (15 to be exact) in the past 3 days from the same number. I answered the one of them, and it had the same 1minute 10s message saying to call the number back regarding a computer threat they found on my computer (the voicemails are all 1min 10s). These calls woke my kids and I up every..damn..day. The calls kept coming on my work and personal line. Without dialing back the number, I'll never know how this crap even started.
I feel bad for others out there who may actually fall for these kind of tactics