I am sorry for your problems, but,
1. I'll never understand why people play with bonuses? I have played with a bonus less than five times of probably around 1.000 deposits over the years and never had a single problem, ever. Well, I could see why people do it. One want to play more/longer and can't afford to take it from your own money.
The only bonuses that are worth taking are those "rescue" bonuses where you play with your own money first and do not lock the money until you reach bonus balance.
For example the ones used on LeoVegas and some other sites.
2. Why do people play on sketchy sites? JimmyJambaCasino, WeScrewYoUCasino, WakaLakaCasino, BennyBeanCasino. Well, you know what I mean? Why don't use the serious sites? There are several sites that are good!
Here are a few casinos that that will give you no problem. I can assure you.
Pokerstars (Casino), Partypoker (Casino), 888poker (Casino), WilliamHill, Betvictor, Videoslots, Betsson, Bet365, Unibet, LeoVegas, Vera&John, Casumo. These are well into the business and trustworthy.
Then we have another lot of decent casinos like Highroller, Rizk, Mrgreen, Guts, Dunder, Bethard.
Yet people are always greedy and fall for these donkey casinos with bad reputation just because of these bonuses.
98%+ of all complaints when it comes to casinos are regarding people getting screwed over when it comes to Bonuses and Terms.
Seriously. Just ban the bonuses and let people play with their own money!
I just listed twelve very good sites/casinos and another six that you can play and withdraw without issues.
I know there is more casinos out there that pose no problem but always stick to the well established casinos in my opinion and always avoid these damn bonuses.