Fake volume is something you can see on most centralized exchanges and if you send them your coins they are not yours anymore.
I never used Mercatox exchange but it does not look reliable and after reading what you posted it appears they have very bad support.
Maybe you can try contact them in public on their social media accounts like twitter @Mercatox_info or in telegram @mercatox_official
Contacted via Twitter, no reply yet. Their TG is just a channel. Last 1 month i am trying. Sometime they forward support ticket to their Finance department sometimes to Security departments, but last 1 month, i can not make withdraw of my 11.63 ETH from that Mercatox.They kept my account locked.