They specified an invalid SHA512 algorithm instead of SHA256.
This looks like a typo. Although it does not do honor to such a site.
I rechecked the hash with the SHA256 algorithm and it is really correct:
Based on your check, it was clear that the hash with the SHA256 algorithm is correct, so the @OP should understand now, and he won't have a problem now. I think it is normal to see a typo on a website because it's happening on many websites out there, not just on one website. And the good news here is he gets a $5 bonus from the site because he shows a typo on their website. I think the gambling website which has a reputation will not do something or cheat people, and if someone can show the bugs or typo or something like that, the site will give a bonus for that person.