Same thing happened to me, fortunately I only transmitted a meager 0.1998 ETH but it's still about 150 USD they stole from me.
ETH showed up on my livecoin wallet address after a few seconds, so everything worked out fine, but it never showed up online. Then a few hours later someone transferred my ETH to another address.
https://etherscan.io/address/0xaa0ce64e90bdd03fcfd2abd0230c0a2f4dad0bcbbe careful if you use livecoin, better go on other exchanges