I lost the contents of a shared folder in iCloud

There are two accounts in my Mac. I created a new one recently and wanted to shift all the folders and photos to the new account. I opened the shared folder in the Icloud section and put all my files and photos in it. I switched off my computer and the next day when I tried to open the shared folder, the photos and files I put in it has disappeared.

[Re-Titled by Moderator]