[dappa]

When it come to disc four all you have to do is keep a track of which moogle wants you to deliver a letter to whom and where that moogle is.

Make sure all the letters are delivered and then head for alexandria and speak to the moogle in alexandria one last time.

You will be sent on a quest to find out who has the item amongst the inhabitants of alexandria. Talk to ruby who will hand the item over.

Go to mognet and hand it to the mail moogle (i forget his name) he will reward you for sortin it out. Lets just say the reward is an accessory.