code: @Override
    public boolean cancelOrder(String orderId) throws IOException {
  
      String[] pairAndId = orderId.split(":");
  
      mercadoBitcoinCancelOrder(pairAndId[0], pairAndId[1]);
  
      return true;
    }
docs: The ID is composed by the currency pair and the id number separated by colon, like: <code>
  btc_brl:3498</code> Please see and use {@link
  org.knowm.xchange.mercadobitcoin.MercadoBitcoinUtils#makeMercadoBitcoinOrderId} .