So the hashed SHA512 of the server seed is different from the hashed server seed they gave to me when I started my session.
The fact that they are providing the hash of SHA512 for you to verify each of your game is their way to prove that they are providing a probably fair game. This hash is your instrument to check whether the results are completely random based from the very first seed they've provided. Thus, different seed from the Hash is enough for you to contact customer support.
If they verify your claim, you could possibly have a refund since it might be a technical issue from their system. Though, these technical issues are crucial to have big impact to the reputation of the online gambling casino.
Its already been provided and its already been verified which do really shows a non-fairness thing and of course it do considered cheating.
Im wondering on why do op doesnt still share the name of said casino so that the majority would able to tell or verify for themselves about this non-fair place.
When we do talk about illegal or cheating then theres no doubt with that.