I ended up with agx.io for now, I canceled all my orders and sent all the coins back into the wallet. I was only one with buy orders there, and still some fake transaction was around me. 
I have buy order on there too.
Nice to know, who nonstop overbidding me there
I wrote to agx.io support, now DCN is offline for trading. But on alcurEX, price is going high, no more cheap buys.