Who called from 7084029171

I get a call from this number several times every other day, no one ever leaves a message and I have not attempted to call them back.

this 708-402-9171 keeps calling me on a PRIVATE and a cell..no one ever answers on "their" end..calling every day.  How can this be stopped?

Been getting regular calls from this number for a couple of weeks. I don't answer calls from unidentified callers & have blocked this number.

708-402-9171 is being used by the Convergent Resources Vultures
(formerly ER Solutions) [http://www.consumeraffairs.com/debt/ersolutions.html].
They are debt collectors for medical expenses, notoriously nasty.