Moogle Delivery items lost when target mailbox is full

So the deal is that I sent 36 items to a friend in 7 sets of 5 and the last alone by Moogle Delivery service. On the 8th mail, the moogle said something about the mailbox being full and the items needing to be returned (or something, I didn't catch it and can't go back). The letter did not appear in my friends inbox, and the last item disappeared from my inventory.

I submitted a ticket, and the response was:
Unfortunately, this type of information is not able to be provided by the Final Fantasy XIV Support Team, since we cannot provide guides and information about in-game mechanics...snip...We Hope you're able to collaborate with other customers to come up with answers...snip

So do any of you other fine customers know what happens when you mail an item to a full inbox and it disappears from both parties?

That's some crazy response you got there from support O.O

OK as an another customer... let me guess... moogle picked up the mail and was on the way to your box but said to himself "why the hell am I going back and forth with this much items for this sender, now return to sender!? Forget it!" and dumped the mail in the woods and went on with his day.

On serious note... You submit the ticket in game? Try sending one ticket on their support site, might get you a better response than that one you posted...

Items missing had gone into armory, and it was just dumb luck that friend only had one spot available in that section, so we believe it had been the last mail being undelivered.

TLDR: Support told me in the nicest way possible that I was a dumbass. :)