Why the items vanished??

It's intended. Yes. Very weird indeed.

Same issue here! I put all of my expansion items (filling all slots) up for sale. It was my first time using the feature and I had no idea what I was doing. I decided that I wanted to use them instead of have them up for trade so I paid to take them down thinking that they go into my storage again and they are just gone! Incredibly confusing and annoying and unfair if you you ask me...

Same here!! Bye bye 6k

Yes, got caught with that too. Should be able to withdraw. Especially since you can't lower a price either. I thought I was pulling something back that was not selling at the price I set, and you can't edit the price, so I withdrew to reprise and ...gone

The global market is not working properly atm. I have had nothing sold for a couple of days even at discounts. When trying to remove the item from the market it vanished, losing 6k in the process. Apparently it is intended, although I do not understand that, it at least should give you a warning message when you remove something, indicating that you will loose it!