Take a self-troubleshoot for some common situations before proceeding. Please include the test result when requesting email support.
Is "Fifine Microphone" seen by your Windows or Mac, or is it recognized as an unknown device?
If it is recognized and the volume level responds when you speak, but you still don't hear audio from the PC, have you selected the correct output device (computer or the mic) under the system and software settings?
If the computer sees it as an unknown device, have you tested it out on a different computer? Tried to update and reinstall the unknown driver a few times on different computers?