Someone is calling me bad things

[Cihan]

Hi, someone is calling me and my family names and is threatening me to do some things to me and my family. I was wondering what I can do to react on this. i know he's from Holland as well, I would like to get to know his IP number, can you help me on it?
Cihan

[nimda]

We cannot tell your his IP address, but if you tell his what his username is, we can check him out.