It would have been better if you fully refunded all those who lost money before starting over again or those who aren't willing investors. Some gambling platforms like Betnomi managed to reversed the negative feedback about them and actually attracted a lot of players (from what I see) but your issue is way worse than them. Best of luck.
That is great of Betnomi but we are just not in the situation where that is possible right now. If I had Bitcoin to refund everyone I would.
I have managed to pay back around $100,000 in the past 6 months hence why the investors are willing to invest again.
But since I can't just refund all myself right now I think taking the approach as some other sites, like ethercrash recently did when they were hacked last week, is by paying back with commission is the best we can do right now.