What broke? You can replace the switches, stock omrons are pretty garbage and it's super common for them to break.

I've replaced the switches in my G604 once, but I don't think I'd do it again. The internal construction is overly complex, so the process took far too long — even though the actual desoldering and soldering was easy. I just wish Logitech would re-release this model with decent silent switches and without the rubber coating.