Hello, i have an annoying neighbour connecting to my network how can i stop them
More aboutblock router
First, ask this question in the Wireless Networking forum.
Use your router's built-in web interface and enable MAC filtering, "permit", and enter your own MAC number(s) as the only machines allowed to connect. You can also use a password, but it's more fun to use MAC filtering because they will think you are UN-secured but still can't get a connection and will mess with their own computers for weeks on end trying to connect without success.
change the name of your wifi network to "stop stealing our internet access" and set the wifi security to wpa2 and you will be good to go.