All the options to avoid those things are available. There is a fix for:

1. unban hax
2. rcon hax
3. Proxy IP bans

Calling of cops is not going to fix anything for you. Use good server provider and you are set.

PS If your owners computer keeps getting hacked then no one can do anything much since hackers can always access server through your owners computer. Get Norton or McAfee or any good anti virus and firewall.