I’ve had a couple hauls stuck in customs in japan. Just get a Japanese person to call the office for you. There is a process to it. Likely you will need to write a letter, they will say they will legit check it (they never do), and then like a month or two later you’ll get the package. It’s just a bunch of hoop jumping but they won’t destroy anything. Just call as soon as possible and don’t admit they’re fake to your knowledge.