What makes you think they are a scam? Because they have a few reports of people not being able to withdraw, or because someone makes a thread saying they lost their money? You need to understand that Fortunejack has literally hundreds of thousands of players, of course there's going to be a few issues along the way because all systems have entropy. You only see the negative reviews because the happy players aren't motivated to write reviews, only anger causes this.
I think its the only persons fault on how they lost their money probably in gambling and playing a lot that they didnt think of the consequences. Something cannot be really perfect and thats why you need to understand that there may be issues.