How far away is your mic from your mouth? When it comes out of the box, the mic is straight (but can be bent towards you). I wonder if that may be why you can't be heard very well?
Are you using the Corsair software or just the windows drivers?
I've only just bought mine and found it to work well for both mic and sound, however I don't currently have installed the Corsair software as it currently breaks the built-in windows speech recognition software that I use. The only problem with running it without the Corsair software is that you lose the 7.1 surround sound.
Have you tried it with just the windows drivers (requires you to remove the Corsair software and reboot)?