I’ve not had this issue, I bought the Celestial Steed for 900 tenders. I received the mount even ran around on it for a bit all before Blizzard disabled the Trading Post yesterday. Logged on today and the mount is no longer in my mount journal and I haven’t been refunded the 900 tenders I paid for it!
Blizzard have had the Trading Post on live for a week now, why not in the week do an introductory quest where you gain 100 tenders and use it to buy a cosmetic hat or some random crap. I love that they are adding more evergreen stuff to the game but please for the love of Illidan: test that sh!t.