Read better its saying ' when using a bonus the max bet is 5€ etc. He is saying that he never uses a bonus because he doesn't like it. If that is the case then the clause is invalid and you should get your winnings.
But I can't say you would get your winnings, I have checked the website for you and it's running one of the worst licenses in the casino industry 'Licence eGaming de Curaçao (#1668/JAZ) '
Sorry buddy. But this happend to many under the same license, you should check some other topics about this, and also learn from the forums. Check what licenses are the best for you.