Hello,
I received a Das Keyboard II (G80) with POM keycaps off eBay, which listed it as clean and in 100% working condition; however, when I finally received it and tried to use it, I realized that the keyboard does not register a lot of keys.

The green keys are ones that work, the grey ones do not work at all. I have tried it on different computers to confirm that it wasn't a problem with the computer.
Is there a way to fix this? I really like the keyboard; it looks good, is clean, and has great keycaps, except it doesn't work.
What are some potential reasons for the keyboard acting like this? All of the switches, even the ones that don't register, seem to be good.
Hopefully someone has a better idea than I do.
Thanks!