I don't think there's much we can do about these exchanges since none of them are regulated. However, you can still try well know exchange like Binance, majority of the community already doing transactions there and they don't have any accusation of infating their volumes on them.
You know it is quite unfortunate that these things are happening. I see it to be as a result of no regulatory body in the crypto market. It has become like you each exchange site has its own way of fixing volumes. Binance is the one i like using and recommend for others too.