Calls from a private number?

So I use to get these calls from "unknown number" and so did my kids. I finally blew a whistle into the phone (suggesstion from Hunter) and it worked the "unknown number" calls stopped. Now today, I have recieved 3 calls from "private number" I answered the first one because it didn't come through "unknown" it came through as "private" and wouldn't you know it no one says anything...just sat there while I said hello. Well, I am no dumby! I just hung up politely and did not answer the next two. Maybe it's not him, but if someone needed to speak to me then they'd leave a voicemail. I thought today was Thursday??? I was wrong must be lame hooverday. Whatever!