hye, my filco MJ2 ninja brown switch got problem, sometimes it doubles input sometimes it doesnt register input, do you know what's wrong? how much would something like this cost to repair? thank you~

Hye, I'm having problems with my filco majestouch ninja 2, sometimes register two times when i type (doesnt happen all the time but really annoying) do you know what might be wrong and quote how much estimated if want to repair? thank you