I think the problem here is that, if any company posts fake reviews about its own performance, the order numbers will always be genuine as it is they that assign the numbers....
I do think that Trustpilot needs to find a way of addressing fake posts, whether negative or positive, especially in light of the stories about people selling their services as fake review writers.
If they don't do that, they will lose their credibility (obviously already happening here) and thus also their commercial attraction to businesses who pay to use them.