I have a good friend that told me the same story, she used Sistemkoin a few times and withdraw all good, then one day she withdraw about 1.5 btc and the coins sent to another address not her, she complain to the exchange and they told het that was her fault, i check the email and the address was correct, she try to contact them trough chat support and the chat window dissapeared, she though this was strange so when i access the site i can see the chat window, so i try to chat with them and they also blocked me too. this happened around February