Help please -- Adobe put my photo and video content in the Catalog

Michel has explained the difference between a catalog and an Explorer file structure. 

Your post does not really explain your problem, so here are some guesses on my part, and also some questions that will help us understand your predicament.

If somebody from Adobe Support was telling you to do full backup (content AND links), I have to assume that you DO use the Organizer and that you DO have a catalog which contains your photos (and possibly your videos).  In the Organizer, you can view all of your folders just like you can in Windows Explorer, by viewing the MyFolders Panel.

See #1 in my screenshot below.  I'm guessing that you are in the default List View of the folders.  You can change this to a tree view by clicking on the hamburger icon (#2) and, in the box that opens up, click on View as Tree (#3).

If you created a full backup, where did you place the backup folder?   If you are viewing it in Windows Explorer, all you will see are thumbnails of everything in your catalog.  Each photo or video file will probably have a prefix of B00.  This backup is not supposed to meant for viewing.  It is only designed to be used when you need to restore the backup e.g. to a new computer or replacement hard drive.

The backup should also have been stored on a separate hard drive e.g. an external drive for safety.  If you placed the backup on your system C drive, it is possible that you placed it in a watched folder and then imported the backed up files into your catalog so that you have duplicates.

We will await a further response from you to see if we have cleared up your misconceptions and perhaps fixed your issue.  If not, please answer our questions.  I am confident that your problem can be solved.

Do you know what a catalog is?

First, it does not contain any of your photo or video files. Only links to the real location of your files on your disks.

A catalog is what is missing in using only the very limited organizing tool which is the Explorer. Instead of relying on the  reader to understand where (in which folder) you have stored your media and organized, structurded and grouped these files in folder trees, it keeps all the informtion ABOUT those files in a powerful database with a lot of indexes to find and group your files with complex queries independently, using virtual organizations in albums, stacks or version sets. For instance you can search from several different search criteria involving .AND. or .OR.operators, or search from a substring of a single word in keywords, captions or notes.

Now, a backup from the organizer means that you should be able to recover both your folders structure and contents AND the associated catalog without which you won't be able to search your images. So a backup folder contains everything for that task, including copies of your media files, the folder structure and the contents of the catalog. The backup restore is able to restore those on a new different drive or master folder as well as over the original location if it has been corrupted.