Who is this & why are they calling me & to make it worse, they don't leave a message!

They have called my work number over and over again.  When I do answer, they hang up...not even responding.

My husband and I both keep getting calls from this number and other numbers like it once we block it. If we answer we get nothing and if we call it back we get nothing. So why are they calling us?

This number calls my cel phone 3 or 4 times a day!! I have pay as you go so I have limited minutes. I also do not have my answer machine on for 2 reasons - 1 because it costs me minutes every time I check messages and 2 because I refuse to use my name in the " you have reached____" It's nobody's business my name especially if they are solicitors!!!! I barely make minimum wage and cannot afford these harassing calls!!!