You could try returning the media.
What are you using to burn the disks? I recommend ImgBurn for most people’s needs, especially burning blu ray. ImgBurn is free to use: www.imgburn.com
When you put one of these disks in the burner and start ImgBurn, it will start in EZ-Mode. Pick Discovery (which in not one of the writing modes, so there is no chance of making a coaster here), and look on the right side of the window in ImgBurn. If the drive has support for these disks in the firmware, it should show a list of Supported Write Speeds here.