As you know Mognet Central has been having a lot of problems; that's why you've been asked to help deliver letters. However, on Disc 3 when you visit Esto Gaza and meet Mogrika (the most beautiful moogle) she tells you that Mognet Central is shutting down because of an "accident". From this point on most moogles won't have letters for you to deliver because of the problems at Mognet Central.

To solve this problem you must first find Mognet Central. You'll need to have participated in the Chocograph Sidequest and have at least the Reef chocobo ability. Go the island North of the Outer Continent and look for cracks in a mountain wall. Feed Choco a Dead Pepper and he'll break open the entrance to Mognet Central.

Inside you'll need to talk to the purple moogle Artemecion. He admits that he used too much of a certain "item" on his fur and there wasn't enough left to keep the Mognet machines running. Now leave and go to Alexandria. Talk to Kupo at the bell tower and he'll give you a letter to deliver to Atla. This starts a chain of letters that MUST be delivered in order to resolve the problems at Mognet Central. Deliver the letters in the following order:

When you deliver the last letter to Kupo you'll finally learn that the item needed to repair Mognet is called Superslick. Go visit Ruby at the mini-theatre in Alexandria and she'll give you some of her hair gel (otherwise known as Superslick). With this in hand head back to Mognet Central and speak to Artemecion. As your reward for fixing Mognet Central you'll receive a Protect Ring.