Game freezes when collecting coins

If you check the console you will see at line 87 you are treating losingMessage as if it was a function by following it with parentheses. This causes the crash. In addition this code always executes because you are using an assignment operator in your condition in the line before

  } if (lost = true) {

I updated your code here as follows

  } if (lost === true) {
        // losingMessage();
        losingMessage.text = "YOU LOSE, TRY AGAIN!!!";
  }

but you may want to add a function that kills the player/stops the game

You also aren't updating current lives onscreen where the player can see. This is because you have you update text twice. For this I added another variable text2

var text;
var text2;

modified the code that adds the text to the game

text = game.add.text(16, 16, "LIVES: " + currentLives, { font: "bold 24px Arial", fill: "white" });
text2 = game.add.text(650, 16, "SCORE: " + currentScore, { font: "bold 24px Arial", fill: "white" });

and the code the updates the text

  function update() {
    text.text = "LIVES: " + currentLives;
    text2.text = "SCORE: " + currentScore;