Okay, the issue happened with PrimeDice, it is very popular, The amount I lost is actually small it's like 0.4BTC and 2ETH... But here are the details of the issue

This is the server seed and the hashed server seed of my bets
https://bitcointalk.org//i.imgur.com/eAo9lTE.png

Their provably fair statement said they were using SHA512 to hash the server seed.
https://bitcointalk.org//i.imgur.com/gwaSzzIg.png

This is the hashed result using a SHA512 calculator
https://bitcointalk.org//i.imgur.com/HjIzbfR.png

As you can see the hash doesn't match... I contacted the support demanding an explanation, this is what they answered:
https://bitcointalk.org//i.imgur.com/QEdzC6H.png

Basically they told me it was just a typo issue, they gave me a $5 bonus "for letting them know about the mistake". I just don't understand how they claim to be the #1 Bitcoin gambling site and making these kinds of mistakes in such important section of their website... That's shady for me, and I definitely will never gamble there again.