I keep getting two-three calls per day from this number and they never say anything. Whats up?

I keep getting calls from this number.  I need to have them stop calling my number.

I am getting several calls a day from this #, when I answer they hang up. I tried calling the # back and received a busy signal (probably busy cause they are harrassing other people). This has become very annoying, it isn't a debt collector cause I pay my bills also deb collectors want their money so they'd say something, this is just a harrasser and how they got my # I don't know.

Someone from this number tried to sell my wife information about an online degree.