A friend just spend 200k on a chest piece and thought the AH had ate the item; however, he finally did get it but the item is buggy as hell. He can't link it and it takes the game a while for it to register the item's existence.
The reason I'm posting this is because everyone thinks the AH is eating their gold and items and that it's just the AH that is broken. That line of bug reporting is only part of the story and won't help Blizzard get the problem fixed. Lets get some details on the item you're having an issue with, like it's exact stats so maybe they can track the item down and see what's going on.