Where did you find this? The Gumroad link doesn't work because the account is closed.

If anyone is reading this, know that no one, not even me, has ever bought this complete set or uploaded it to other sites which makes this animated sample a piece of lost media.

staindVEVO said in comment #2624466:

Where did you find this? The Gumroad link doesn't work because the account is closed.

If I may point out, this was uploaded two years ago. Presumably the account was still open at the time, thus allowing this sample to be uploaded. I somehow doubt the user themselves actually bought the set it was advertising, but if you're really hung up about it, you could DM them directly to confirm.