Call back gets, "Hi, you've reached Robert and Julie, we're not available now. Please leave a message....." Does it sound like someone you know? If not, maybe they just dialed the wrong number." There is however a post on "whycallme.com" that complains of getting calls from this number twice a week despite being asked to be removed from a list. Here's the site:
http://www.whycall.me/313-578-1478.html.
With call spoofing, it's hard to know.