It took my gold & says the transaction is completed, but the item isnt in my stash or the send to stash area. What happened?
Sometimes, especially during peak activity on the Auction House, it can take a few minutes for things to appear in the Completed tab. Occasionally I've had good luck getting things to appear here by entering and then leaving the game.
If it's been more than a half hour or so, you might want to post a bug report in the official Bug Report Forums.
This happened to me three times already, so I thought I would add my 2 cents. After every attempt to release the "missing item", what eventually worked was to buy an item of the same type. For me I bought a spear worth 1 million to release the "missing" spear I bought for 22mil
Keen to know if this works for anyone else, or if it was a fluke. The item was missing for almost 3 days until I got this right.