The only thing I can think of right now is to upload a .htaccess file into the directory where the link is. The .htaccess should contain something like DirectoryIndex /
. This would allow any visitors that go to a page that does not exist to be redirected to your main index page.
If you have another index file inside that directory, then you will have to add it into the .htaccess file also. Like, DirectoryIndex / index.html index.php
Another way is to setup a 404 error to redirect to the main page.