Download private content

Hello. Currently, I paid for an online course, which I access via a specific webiste, authenticated with my cresentials, and I would like to download the course' videos. My OS is a linux based, and I tried several chrome extensions for this purpose, but the only was able to download the videos was the video downloader plus, however, the downloaded videos had no audio. I would like to know some alternatives for this purpose.
https://www.reddit.com/r/Piracy/comments/1aitfzi/download_private_content/