True. Some of those trolls are actually employed by rival casinos which is why valid proof as you mentioned helps a lot.
It's the case with most of casinos where reputable and legit casinos are targeted by spammers without any valid evidence and just trying to defame them so people start arguing about it and raising concerns but that doesn't helps a mot because the players who are gambling regularly with casinos like Roobet know they won't scam them with few hundred or thousands bucks unless players have violated any of the casino terms or trying to cheat them.So trolls should be ignored without giving much attention to them which they desperately need.
While I agree, all cases need to be researched by the team as you will always have some legitimate cases. Costumer service is service underrated but so important for any company. I just checked trustpilot and to my surprise, they score extremely high over there: 4.7/5. Never seen a casino so high as most of the times, you will have more complaints than positive reviews on there.
Those legitimate issues will be solved by providing validate evidence along with those claims and it happens many times and casinos let them withdraw the amounts after the matter is resolved.Sometimes it's just a suspicious activity from a account that led to this issue but it is resolved apart from those all just trolls and spammers trying to cover their loss with cheap tricks.