Question @Best_Change:
If you take a look at exchangers list, most of them are with 0 (ZERO!) negative reviews, because if you post negative review they invite the exchanger to comment and all that exchanger have to to is to click "cancel claim" and your negative review becomes a comment.
Is this true? If so, that makes the review system worthless, but it does explain why there are no persistent negative reviews on any of the exchanges you've listed.
If this is indeed true, can you publish this as a warning in bold on the review page? It seems misleading to omit this.