[MichaelDance]

I would contact your webhost, with the last known IP for him.

They can ban him from their hosting server and that should solve it, Change the admincp URL.

In config.php

// ****** PATH TO ADMIN & MODERATOR CONTROL PANELS ******
// This setting allows you to change the name of the folders that the admin and
// moderator control panels reside in. You may wish to do this for security purposes.
// Please note that if you change the name of the directory here, you will still need
// to manually change the name of the directory on the server.
$config['Misc']['admincpdir'] = 'admincp';
$config['Misc']['modcpdir'] = 'modcp';

change the admincp to something else and the modcp.

This should stop him, put a password on the folders,

CPANEL > Password Protect Directories > click folder url, then tick the box put a message save. > Add user and password to them and then save again....

I hope this helps if not, change host or everything linked to this childish kid.