Intential sheeping quest mobs

Hello!
Wanna do it. Today me and my party members got problem with player Gini (mage 26 lvl).
We are doing quest " A Grim Task". When we go to respawn place, we find another party.. We are started the kill quest mob but hes bugged and lose. After this guy started using non-stoppable polymorph for mobs around respawn place, than he disturb us to killing these mobs.
His reason: we are steal their mob. But if thay stay so far from him, i think it wasn't steal.
Pls solve this problem with this guy, because considering more players on server it is integral part of lvling. (who fast that cool).
This links with pictures as proof for his actions: http://imgur.com/E5ERJJ9
http://imgur.com/uifFcQB
http://imgur.com/p2fvD6Z
http://imgur.com/nB6x2F9
Wanna do it. Today me and my party members got problem with player Gini (mage 26 lvl).
We are doing quest " A Grim Task". When we go to respawn place, we find another party.. We are started the kill quest mob but hes bugged and lose. After this guy started using non-stoppable polymorph for mobs around respawn place, than he disturb us to killing these mobs.
His reason: we are steal their mob. But if thay stay so far from him, i think it wasn't steal.
Pls solve this problem with this guy, because considering more players on server it is integral part of lvling. (who fast that cool).
This links with pictures as proof for his actions: http://imgur.com/E5ERJJ9
http://imgur.com/uifFcQB
http://imgur.com/p2fvD6Z
http://imgur.com/nB6x2F9