I guess it depends on what the customer was saying the problems were. If the customer is not getting back to you, there is not much you can do. I'm not certain that CGTrader support can do much for you. Leaving a bad or good review is a customer's prerogative, and I don't believe that support will police that.
Many customers do not leave any kind of review, so it suggests that they are satisfied with their purchase and just don't want to take the few extra minutes to say so. A negative review without explanation can be frustrating, especially because you don't have the opportunity to correct whatever issue it was, it there even WAS and issue.
The review process on this website can be improved, but I really don't have any recommendations on what would be better. However, I do get a bit overwhelmed at every business wanting my time to review every stinking purchase I make or any kind of service I get with a 10 minute interview. Perhaps the review should be just a quick pick of stars or something that just takes 1/2 a second to do. But you would still have those who would just be mean and give a bad review because they are just mean spirited.
