I've read some of the reviews that are on Trustpilot, some of the negative comments came in concurrently, I wouldn't consider this to be a deliberate thing to do, however the reviews are mostly preposterous and they can't provide any evidence more. As an example is
this review. Lately Rollbit seemed to be attacked by their competitors.
Trustpilot reviews can be biased by teams or attackers. It is not good enough against bias factors so if you look at Trustpilot reviews, you should consider them as reference, additional source but are not your main sources to rate one platform.
Generally don't rely on third party reviews and take risk or put big capital on a platform you have never experienced with. It is painful for new platforms to fight against attacks but when it is big enough, who care about biased and negative reviews from attackers who always chase big platforms.