manipulation of sell oder

I placed a sell order ,and close with a loss of about 7.6 dollar...but when I clicked on close sell order ,it will displace buy order very fast and close my sell order...only to open my mt5 and want to trade I saw a buy order loss of about 8 dollar ,I didn't open a buy order,I reported it to one of deriv agent I know ,and he was given nonsense excuses..