I just have read something i thinked that was works
i tryied this :
I know that alot of people have been getting Realm Downs lately and I do to. So I will tell you how to remove those IP bans. This works for user with "always-on" connections such as cable, dsl, or LAN. If you have dial-up then simply reconnect to the internet.
1. Goto Start >> Run >> Type CMD
2. Then type in IPconfig/release
3. Then type exit or hit the Close window box
4. Now goto Start >> Settings >> Network Connections
5. Double-click you LAN connection
6. Click on Properties and from the list select Internet Protocol
7. Now select "use the following IP address" and just type in random numbers. Then hit Tab and the subnet mask will default
8. Now click ok and accept all that.
9. Go back to the Internet Protocol area and select "obtain IP adress automatically"
10. You should now be able to get onto battle.net again