Unable to transfer character; optional item stuck in Mogmail

Time: 5/4/16 approx 7 am EDT
Frequency: Ongoing
World name: Gilgamesh
Character name: Nameless Protagonist
Retainer name: N/A
NPC name: Delivery Moogle
Monster name: N/A
Class/level: White Mage/54
Party or solo: Solo
Race: Rogedyn Female
In-game time: N/A, ongoing
Area and coordinates: Limsa Lominsa Upper Decks (11.5 , 14.3)
Housing: None
Steps:

-Logged into an alt character to transfer to another server.
-Cleaned out and recieved all Moogle Mail on ALL my characters, usuing the reward request button when applicable.
-One item on listed character is missing; the Bennu Horn (chance that containing mail may have been mistakenly deleted).
-Tried to use world transfer service, get following errors:

- You have purchased optional items that have yet to be claimed.
- This character has a name change pending.

I do not have a name change pending, nor does my change of server request require one. My issing item is stuck in limbo and cannot be recieved.

Tried to get a step further in the transfer process with my other characters; problem only occurs on listed character and all others can proceed with transfer no problem. Listed character is the only one I want to transfer.

Sent a message out to the support desk, reply simply states to post the problem here.