World chat hijacked.

During restarts this morning (14/3-15) world chat got hijacked by an player called ganickzed
(changed it to password protected.)
Proof : http://piclair.com/v2t3r
Is there anyway to make worldchat / global not being able to be altered by the players?
(changed it to password protected.)
Proof : http://piclair.com/v2t3r
Is there anyway to make worldchat / global not being able to be altered by the players?