There are a few possible answers
1. The default page is stuck in a cache and you aren't seeing the new content yet. Try refreshing your browser a few times. If that doesn't update the page, call it specifically by typing http://www.yourdomain.com/index.html.
2. Check you have uploaded your files to the correct directory. The main website is at the /public_html (cPanel), wwwroot (HELM), httpdocs (Plesk) directory.
