I’ve replaced the stock cooler with an aftermarket one (I had to break the warranty sticker on the screw) on my Club 3D HD7750, some time later the card stopped working (black screen, checked on two computers). I’ve read on the Internet that I need to put back the stock cooler, so I did and I sent the card to the seller. A month later I’ve been told that they can’t replace my card because the warranty sticker is broken.
For example here you say it should be fine: https://insights.club-3d.com/thread/club-3d-and-the-stock-cooler-warranty-in-eu-2/
Can I send the card directly to you? Is breaking the warranty sticker fine with you?