There have been so many accusations and counter-accusations on the subject matter of fraud so many players have come out with evidence of scams against some sites while the operator of those sites come up with counter-accusations that players violated their T&C.
I think it will be proper if an online accredited court is set up to judge such cases, rather than leaving them uncensored.
If gambling is legal in your country and the gambling site that you are using is already registered then you have to understand for a fact that you can apply for a case online since most of the times the governmental bodies have online FIR and then you can also publish them and find your solutions if other people had the similar probelms as well. Now a days social media has also become a very powerful platform as well. Most of the companies are able to show their services through how well they support their customers through.
I always prefer:
Playing on already known site with good reputation
Trying out new sites without negative trust who are involved in campaigns
This generally helps and you can also go to their personal thread and see if there are any problems as well.