Recovering items decayed in mailbox

I had all of the plate heirloom items as well as the 2H and, I believe, several trinkets. Shortly after hitting 80 I think I mailed them to my level 58 DK, the only other plate-wearer I had at the time that I was considering leveling. A few days later I took a break from the game, not logging back in for many months.

Now I'm trying to level a paladin but have none of my heirloom gear. I assume what happened is that the items sat in my DK's mailbox untouched until they were eventually returned to this characters mailbox, where they sat until they eventually decayed.

I opened a ticket a few days ago and was told that I would have to provide the character names and general time frame. After opening another ticket and providing the requested information I was told that they simply had no way to verify whether I every owned the items.

So which is it? Is there any possibility I could get these items recovered? I find it hard to believe that there are no records kept for this sort of thing.