The old shops are now called legacy shops. You can still sell if the items are already priced but you cannot reprice or move items there. You need to make a new shop. There is more information about the move here https://subeta.net/forums.php/read/854270

Once you create a new shop you can see all old shops and galleries on the dropdown shop menu. The old shops were basically killing the site

This is my dropdown. The 3 shops that have the triangle with the ! are the legacy shops. Can you not see this on your dropdown?