I recommend you take a look over here:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s
The first thing you need to look for is the reference to how to report a problem. Your
problem description is rather vague.
The other thing you need to look for is the discussion of video without audio & audio
without video. This is not a new issue. It has been raised many times before. You want
to read up on the subject in the threads referred to in the Table of Contents thread. Or
you can simply search for the topic in this forum.