Hi from the reviews of this keyboard it seems like a promising keyboard. Before anything, is it possible for you to try and connect the keyboard to another system, or a laptop, or even using USB OTG to an Android device, like a tablet or a phone, to see if the keys work there just fine?
If you connect the keyboard to another machine or device and it is still acting up then there is a problem with your keyboard. I don't have it, I don't know what technology it is using for the keys, but It is possible that there is a loose wire or misplaced connection or dirt somewhere. If it still has a warranty try that before opening it up yourself, but if you know what you are doing and want to try your chances, open it up, have a look at connections wires, the surface, try using a multimeter looking for damaged connections or wires.
It would be very helpful if you could take pictures after you have opened it and post them here for the reference of people who have it if they might find themselves in a similar situation and want to repair it themselves.
But if it works just fine on other machines, then it is possible there is something wrong with your drivers on this particular machine, since you have tried removing and uninstalling the driver for this keyboard, try also uninstalling USB drivers and restarting the system.
Do not do this on your machine if you have a history of malfunctioning USB3 devices and or it is hard for you to get USBs to work. Because this action would remove USB drivers.
Hope this helps in someway.