Hmm, the problem still exists.
I'm getting mails from 2 months ago every day.
Obviously only a few people are having this bug, but it would be nice, if this could be solved although.
this has been a long term problem that started with season 3's release. there has already been several other threads on the subject and it was mentioned in one of the engineering reports as being Under Investigation.
i'd suggest that you submit a bug report.
as you seem to have found out, items that expired are returned to the character who posted them are can only be picked up from the mail / viewed by that particular character. its possible that you deleted these mails thinking that they were empty before you realised this. in that case the mail will continue to be sent empty until customer service resolves the problem for you....
it may take a couple of months if its a bug report.
my missing expired sale items took 8+ weeks at an estimate before they were returned.
i'd suggest that you stop deleting the emails in the meanwhile, limit the amount of characters you use to sell with and regularly take down items before they expire and reprice them etc.
other than that possibly send stormshade a pm, he'll love me for suggesting that :p - but thats what he's here for, to liaise with customers.
it'd be nice if the developers would make some form of announcement regarding the status of this issue though.
One of the updates changed it so instead of expired auctions being accessible by any character on your account it is only accessible, (retrieve expired item) from the character that put it on the exchange.
If only the posting character can see or retieve the item, then they should list the character name in the email. That would pretty much solve this issue.
There was a WoW add-on I used to automatically take items lfrom mail and delete the mail. I just had to click one button and it solved all my auction spam.