If you have everything set up correctly (5 basic checks if Voicemod doesn't work article), your friends hear your transformed voice or your memes sound, but you can't hear your meme sounds or your voice (with the option HEAR MY VOICE enabled) maybe it is a problem related to the Windows mixer.
Follow the next steps to reset it:
1.- Open Voicemod.
2.- Go to the Voicemod Settings->Advanced settings tab.
3.- Disable the anti-popping mode.
4.- Disable the exclusive mode.
5.- And without closing Voicemod (this is very important), resets the Windows mixer:
- Open Start -> Settings
- Go to "System":
- Click on "Sound".
- Look for "Advanced sound options" and go to "App Volume and device preferences":
- Here, click on "Reset":
Make sure that you don't have the option "mute for me" activated: