I needed to block my ex's number, but he calls private normally. I was wondering if I called my cell phone company so they could block it, would he still be able to call me from private? I hate my phone ringing nonstop. Especially when I'm with my boyfriend because he knows its my ex.

Actually when the number is private that means it doesn't register. Also that wouldn't stop him from changing his number or changing the phone that he is calling you from. Either deal with it on a temporary basis or change your number. Generally speaking if you stop answering the phone, he will eventually stop calling. If he doesn't contact the authorities and get him for harassing behavior. Good Luck