where to check warranty registered date?

in my account i boungt RAZER BLACKWIDOW ULTIMATE 2016 - MECHANICAL GAMING KEYBOARD, and registered it, but i lost the evidence of purchase, where can i check when did i register? or how can i send it to fix for warranty? i am from Taiwan. i remeber i bought this no more than 2 years but now the keyboard some key is now good, you have to hit many time to get the responsed.