We have some problems with your product. I need a service manual to check for potential problems, so can repair it ourselves.

Unfortunately, we do not provide technical manuals to end users, you can contact customer support for assistance.

I cannot find the KB-G235/KB-G255/KB-G265 driver to configure the multimedia keys, other keyboards have drivers to easily manage those keys.

This is a plug-n-play device, it uses the Windows default driver. Check the manual for which keys to press to access the multimedia keys. If you still have a problem, contact customer support.

What is your global warranty on your products?

Unfortunately, we do not offer global warranty on our products.