Problem with legendary quest

Hello there....By the way i hope you are havig a good evening. So my problem is that i completed the whole part of the legendary quest for Thunderfury weapon, i completed it all till the quest that you need to kill the Prince.. The prince appeared to me, i killed him but when it was time to loot the (mob) i couldnt take the item it dropped so i could finish the quest and complete the whole chain quests... After months of trying and lots of golds suddenly i am in a deadend...A gm responded me that he cant support me on that issue i had but that wasnt very helpful at all. So i write a ticket in website here to talk with a gm and find a solution on my problem.
I will be waiting for you reply......Thanks a lot in advance :) :)