Since MetaMask is an Ethereum wallet, it shows your balance of ethers the current amount of which is 0. Tokens are stored in a separate balance and can be viewed through the game interface. To transfer RLT to Livecoin exchange you need to log in your Livecoin account, go to the page "Balance" (the tab is located at the top of the page) and enter RLT in a search field. You will be offered four currency pairs available for trading RLT/BTC, RLT/ETH, RLT/USD and RLT/RUR. Please, select one you want to exchange your tokens for. After that press "Deposit" button and in a newly opened window enter your MetaMask address.