You can try Account Search to see if those items are still in your account. In the new wardrobe, you can try to search for them by the item name. Make sure you have "Only show item you own" checked, and make sure all the other search filters are set correctly too. (For example, "Layers" should be set to "All", and "Show" should be set to "All items" to show everything.)

If you think some items have vanished, you will have to file a ticket to see if a UA can figure out what happened to the items. However, I don't think it is possible to lose items by opening the old wardrobe, so there is a good chance the items are still on your account somewhere.