I am fairly sure the Gamemasters can not help with this kind of things, and that progress in such quests can not be altered.
If the item recovery could be used for this kind of things, they would need to be doing it a lot for a large number of players who are requesting such things due to a change of mind, or whatever.

As far as I know, they have that ability to recover items that were lost due to a game- or user-error, or if the account was stolen and items were lost this way and even in those cases, the number of times they can do this is limited, expect for the cases where items were lost due to a game-error.

It is not for players to be able to re-set quests or return items already used for them.


At Square Enix Support Centre, see the Knowledge Base Article: 12645


I can't really point to anything other official right now, so this is obviously just how I see it.
Perhaps we will get an official response soon'ish. ^^