hi everyone, I have exactly the same situation
after successfully exchanging coins for bitcoin
I wanted to put on another exchange
before that the sums were insignificant and everything passed without problems
immediately after the request came a confirmation email
I confirmed the withdrawal of coins and started tracking 27.11.2018
and immediately noticed that the wallet address(34C8F5DHqNKXpijZFjYprCHEXpzdS57FMD) does not match mine specified in the request and confirmation

(Please confirm your withdraw
Coin: BTC Amount: 0.31189327
Address: 1Ly3i7zcwKr8TmsFRVshbYhJjKMpoqPbTU
Confirm Withdraw
Please click this url for confirm withdraw.. https://sistemkoin.com/api/confirm/withdraw/MMmttGjmXLhdHGTcPeRhH8agYaV7ZSz5hwh1aUUs7PA9NRGZJ7kAgL6mgbLY)

after contacted support
in support was told that everything went well and provided a hash of the transaction(85dc154aac714d3c1ef01aeb0865a9d70e9232a18407d0407e4fb56606accd04)
I wrote many times asking to resolve the issue and at one point I was turned off the ability to write in support

recently I again had the opportunity to write in support and one of the answers from them was maybe your account was hacked
I had never received an official response before from the administration where did the coins go