I've contacted to Novaexchange about my lost XCN, they do not see any transactions to the wallet, but Suprnova shows coins were transfered.
What should I do in this case?
Use a third party source, like a block explorer, to show them the coins.
As pallas said, I provided to Nova support block info with my transaction. Coins appeared in wallet few hour later.
Now Nova refuses my sell orders - "Trades for XCN has been disabled, probably wallet issues. Check coininfo under balances."
Coininfo shows - all ok.