Non-working number.  They left no message!  These types of callers waste so much time - and get nowhere!!!

Please don't assume it's a telemarketer.  Be cautious and assume the worst.....just as you would as you contemplate opening an email from a sender you don't know.  The call could be coming from a source trying to determine if it has found an in-service working phone number.  if you answer, you have given them what they want.  The goal is to use YOUR phone as the source for originating fraudulent activities.

I called them back, and their automated system answered.
It's definitely unwanted sales. Telemarketer.

Didn't say anything within ten seconds of calling. Called back and got an automated system which did not specify the name of the company. Obviously telemarketers.

I missed the call and returned it. I got a non-specific company offering to either connect me with a representative or select #2 to remove my number. So now they'll call me from a different number. =/