Even though ManyCam Virtual Microphone is not selected as your microphone, this does not prevent you from being banned because this site has access to your list of devices, including all mics and webcams so it does know that you have it, hence disabling the ManyCam microphone is mandatory to make this work.
Here’s what you need to do:
- Close Firefox and make sure it’s not listed on Device Manager,
- Disable the ManyCam microphone on Windows settings as I suggested above,
- Rename ManyCam Virtual Webcam in ManyCam’s Settings and make sure to save the changes by pressing Edit, when picking the name, go with something like Logitech C615,
- Restart ManyCam,
- Now run FireFox and try again.