Folks ignore Steve, all his suggestion would do is cost you more money on your phone bill. Do not call these people back. Just get yourself a call blocker, and block the calls.
Received a call while I was out from the number 312-614-1105. It also said "L7 SCVC Call" on the Caller ID. The call stayed on long enough to show I had a message but there was just dead silence. I think we're all getting tired of these crap calls!
Two calls (3:28 pm & 7:46 pm Mountain) from this number - as noted before, caller ID displays L7 SCVC Call. Did not answer - no message(s) left, added to blocked numbers list.