received 3 sets of double calls from this "unknown name" caller one evening, where the second call was placed one minute after getting my v/m and hanging up.  The third set of calls came at 10:47 and 10:48pm, so I finally answered in hopes of getting the call to stop. When I answered there was noise in the background, but they didn't answer my questions of "who is this?"  Calling the number now results in a fast busy.