Have been receiving calls from this number over the last several days. It left me a voicemail of a few seconds one time; otherwise, no message. Thankfully I searched here and have added my complaint with the FCC, for whatever good that does. Really frustrating, though, as I am sending my cell # out on resumes and do usually answer, even if I don't recognize the number. I am also located in Chicago - I would bet they use "local" numbers for each area they call (although, really, to a Chicagoan, the Springfield area code isn't local or recognized).
Many thanks to the people who took the time to figure out which company we're dealing with, etc. I hate wasting time trying to find a human that will talk to me.