#1

1- Get a serial number of the product you want you could find 1 in my discord server: https://discord.gg/axuEnY2yns
2- Visit logitech support either by calling them or live chat (if you have good communication skills call better)
3- Tell them that you're keyboard unresponsive keys or not detected ...
4- They will ask you to return it to the retailer you are gonna say you already did and they gave you a denial letter (you could also find it in my discord server)
5- If they asked you about proof of purchase you could get one on my discord server or photoshop one
6- They will ship you the product use your real address 
7- If you are gonna abuse the method use fake emails

To Get Serial number or pop or denial letter join my discord server:
https://discord.gg/axuEnY2yns