I called back the number and got an answer.  The person was rude and would not answer  who they were calling from or what the purpose of the phone call was about.  They only wanted answers to their questions about your name, address and personal identification information.  After I hung up on them I  called my local police to try and report them and to also find out what to do.

No message - called back, fast busy signal (bad or masked number) - scam.

No message, Illinois Caller ID; believe it maybe "skip trace" component of a collection agency

Got'em The caller is ARS, using variations of 312-436... w/ILLINOIS CALL id and hanging up w/o a message in the beginning,  later using the "skip trace" lines (for outbound only) calls leaving messages to call 866-725-4895 x3145 & x3204.

I will send complaints to the BBB and FTC (for starters) about the many hang up harassment calls; lack of official or professional identification, no "mini Miranda" stating who was calling, purpose and phone number.

This number/line is used also for "skip tracing". Guess when they can't skip trace, this is an outbound line. The "caller"  says to call 866-691-4895 x3145 or x 3204. ARS is playing games first they use the skip trace to call anytime and hang up; using variations of 312-436 numbers with a ILLINOIS CALL id sets up the automated dialer. A few "collectors" might call after or before shift changes, and train new hires.

Unknown number called and left no message.

yes its a collection agency, they think they are slick.  To all know your rights.  Once any business writes off the debt and gets the tax credits for it they can no longer collect.  but scum like this use strong arm and fear tatics as they pass files from agency to agency.  most will only spend 6 months on any given file.  how do I know? I have a law degree and did this type of work while in law school

I've gotten a call from this number twice now.  I screen my calls, and if it's important enough from a caller I don't recognize they'll leave me a message.  Neither time that this number has called have they left a message, therefore, I believe that it's a fraudgelent telephone call.

A guy named Greg Walker calls from this number attempting to collect debts