Got another call (today at 3 pm, same day) from this number; after holding for a few more seconds (than this AM), a person came on the line to ask for an "unknown" person (that does not live in our household).  We've had previous calls asking for this "unknown" person over the past 10 years that we've had this telephone number.  It's likely that "unknown" person had this phone number before it got assigned to us (about 10 years ago).  We've had numerous previous calls for this "unknown" person ... from debt collectors, credit / loan amalgamators, etc.   I asked the caller to make sure the SOURCE of their telephone number info is informed that this "unknown" person is no longer associated with our telephone number, (and haven't had for the past 10 years) and the SOURCE corrects the error.