Shadowmourne sealed box

Hello.
I've finished the Shadowmourne quest line, but I was not aware I needed to loot Lich King's body afterwards. I thought the box and the items in it will be awarded from the quest. So I've got my Shadowmourne, killed the Lich King and handed in the last quest. However, as I did not get any items, I went back to the body to try to loot it but there was nothing.

Is it still possible to get the awards?

Thank you.

So even after killing LK 25 again, there was nothing in the loot. Could some GM please remove the last shadowmourne quest from my character, so I could loot it next time? Thank you

You'd need to write in-game ticket.

Just know that usually GM's don't help with lost items obtained in-game.