ES6 class methods not a function

I'm messing around with Javascript "classes" and I have a paddle that has a proper method to draw, but for some reason my moveBall function is messed up. Could anyone point out why? I get an error saying that moveBall() is not a function.

Edit: I included some more code, I call init() to start it all.

class Ball {
    constructor(x, y, r, sAngle, rAngle) {
        this.x = x;
        this.y = y;
        this.r = r;
        this.sAngle = sAngle;
        this.rAngle = rAngle;
        this.speed = null;
    }

    drawBall() {
        ctx.beginPath();
        ctx.arc(this.x, this.y, this.r, this.sAngle, this.rAngle);
        ctx.fillStyle = "#FF0000";
        ctx.fill();
    }
    moveBall() {
        this.x += this.speed;

    }

}


function init() {
    var  ball = new Ball(c.height / 2, c.width / 2, 10, 0, 2 * Math.PI);
    var paddleLeft = new Paddle(0, 0, 20, 100);
    ball.ballPhysics = 1.0;
    draw(ball, paddleLeft);
    main(ball);
}


window.main = function (ball) {
    window.requestAnimationFrame(main);
    ball.moveBall();
    window.onload = function () {
    document.addEventListener('keydown', function (event) {
        if (event.keyCode === 65) {

        }
    }, false);
}

};