Here are the relevant rules that I stripped from FortuneJack's Terms of Service:
8.1.1. On Slots, Casino Games and Live Games Your deposit amount must be wagered, be turned over 2 (two) times;
8.1.2. On Sportsbook Services You have to make at least one bet with minimum stake of 50% of Your deposit amount (example: if Your deposit amount is equivalent to EUR 100, You have to bet minimum EUR 50 on any position You can select on Sportsbook Services);
That second rule is insanely scummy: I have actually never seen anything like this before on any casino.
Suppose someone deposits $2000, hoping to play with proper bankroll management with sports betting and instead they have to actually drop down $1000 on a bet. What kind of ridiculousness is that? It doesn't even stop any abuse: if someone really wanted to avoid that rule they would simply deposit in chunks, thereby making the minimum stake far lower. For example, depositing $100, 20 times.