I get those calls at least 3-5 times a week. No voice mail gets left and I don't want to call them back from my home or work number because I know that whoever this is will contact me on those lines. Until they leave a message or identify themselves, I will not be calling them back.
I get calls on my cell and I decided to call back on my office phone and I stayed on the line it eventually went to a dead line. I then decided to call back on my cell and it did the same thing.