Mail Recovery confusion

I missed collecting my mail of expired Auction House postings by a few days. Just procrastination and leveling alts. I wasn't too panicked as I was aware of the self-help Mail Recovery option in Support.

So I went there and started the mail recovery wizard. Chose the character and realm. After a long wait while the process searched, **all the mails I was interested in were listed** - 8 pages of 10. I individually checked all of them, then Recover. Long wait while processing, then empty page with message: no eligible mail available.

Hoping this was just their way of saying job done, I waited and re-logged my character a few times, but no mail appeared.

I sent a support ticket which was gave a standard reply:

>Customer Support doesn’t restore mail, as mail will remain in your mailbox for 30 days. After 30 days, the mail is deleted and any items or gold attached to the mail is lost.

>You can use our mail return page to restore sent, deleted, or expired mail. You will receive the restored items in your character’s mailbox.

>Limitations

>You can restore mail once every 15 days per Word of Warcraft Account. The service cool-down is shared between World of Warcraft and WoW Classic.

>You cannot restore mail if:

>- You don’t have game time or an active subscription

>- Your account is suspended or banned

>- The mail has expired after staying in the mailbox for too long

>- The recipient has collected the mail from the mailbox

I am not understanding how "You can use our mail return page to restore sent, deleted, or **expired mail**" and "You cannot restore mail if ... The **mail has expired** after staying in the mailbox for too long" makes sense. I am not aware of any other category of expired mail.

And why were the mails that had just expired from "staying in the mailbox for too long" presented to me by the wizard as candidates for recovery?