I also got a call from this number, from Denver - don't know anyone there, didn't answer.  Called back on office phone (multi-lined) and received a recording that stated:
'none of our representatives are available right now, if this is the number you received the call on, you should receive a call back within a day.  If you believe you received this call in error, press 5 to be placed on our "DO NOT CALL" list'.  I hit '5' and then blocked them on my cell phone as they never told me their company name or any reference.  So, if it's really legit - they can mail me something.  you would think that they would at least give you a company name.