Yes SistemKoin is a scam.
There are many reports that when users do withdrawals they send the coins to a different address, and when a support ticket is open they reply saying is user fault, if you respond then they stop replying and ban you from the live support chat.
They also do shady IEO and looks like all projects are created by them.
Also many wallets have problems.
Stay away!
Actually I have heard similar nightmares from other users about Sistemkoin. Who the hell lists their coins in such shitty exchange?