Blackwidow V3 Pro Keys Not Working

Hi all, I received a Blackwidow V3 Pro to replace my old Blackwidow today as a birthday present. However, the majority of the keys on it don't work... It isn't in one place and is spread out over the keyboard; over half of the keys don't work. This makes me think it can't just be a hardware fault. I've followed all of the troubleshooting guides, including downloading the firmware updates. I've also followed the guides to take it out of "demo mode" (although, if it was stuck in demo mode, following the guide wouldn't help as caps lock and space key are two of the keys which don't work!). Any advice? Like I said, because it's spread out over the entire keyboard randomly, I am convinced it isn't just a fault keyboard. Thanks :)