From what I got to know about this exchange, Sistemkoin, it is a Turkish cryptocurrency exchange with a well designed platform it supported fiat currencies as it has its own available fiat market but today, it appears that this exchange is no longer available for traders and investors as well.
As I once heard, Sistemkoin was under maintenance for a while before it went off. When I got to know about this exchange, I found out that it was under maintenance so I decided to wait for a while until things settles down on its platform but after checking again, it turned out that it is no longer available. Also, Sistemkoin has been marked as untracked listing on coinmarketcap. So I will advise you to check out for other exchanges.