Cooper Tire review: Defective tires

I purchased a set of 4 Cooper Discover HT+ tires, DOT numbers UP80CLD4721. The tire tread warranty was 60,000 miles; but had to be replaced after 13,000 miles. The tires were defective according to our local mechanic and Car-X who sold me the tires. Cooper Tire would not respond to the request for a refund on the tires. Car-X sent the tires to Cooper Tire and were returned back to the shop with no refund. That particular tire design has been discontinued.