I’ve used Ks quite often. They are generally my go to for boards as I’ve had great service from them In the past but have never had to deal with a warranty issue with them. I’ll def think twice about purchasing from them in the future if this is how they deal with defective board issues and their customer service on the service/warranty side sounds like it’s ran by the Soup Nazi.
What did you do with old boards? I’d be willing to buy them off you.