You can request data on your character's transaction record. I can't check the transaction records of the third party.

Information on unfreezing an item in the Trading Post

List of connected realms and information on how connected realms work.

What to do if you regret spending your celebration tokens

How to install a Blizzard game you already own on a different computer

What to do if you've been scammed

What to do if a Delve companion has been levelled to an eligible achievement milestone and no achievement is awarded

The counter of the achievement Trading Post Enthusiast does not increase after completing all requirements for the monthly reward

What to do if you are unable to get the password for Myza's Oasis because you can't interact with the trade items.

What to do if you cannot see the item you previously froze in the Trading Post