i created a custom webhook endpoint to receive data from moosend. The idea is to get the email address of a new subscriber and create a new customized coupon in woocommerce. I created an automation on moosend which triggers the webhook successfully. The coupon is created but i cant figure out how to get the email address of the new subscriber from the data which is being sent. As far as I understand, the data is being sent via this schema:

http://cdn.stat-track.com/send-to-webhook-context-schema.js

This is my approach so far (i tried different methods but none has worked )

    add_action('rest_api_init', function () {
  register_rest_route('webhook', 'newMoosendSubscriber', array(
    'methods' => ['POST'],
    'callback' => 'createDiscountCouponForNewSubscriberME',
  ));
});

/**GENERATE COUPON */

function createDiscountCouponForNewSubscriberME(WP_REST_Request $request)
{
  // create coupon
  $email = $request["properties"]["Event"]["ContactContext"]["properties"]["EmailAddress"];

  $coupon_code="welcome-" . $email;
  $amount="10"; // Amount
  $discount_type="percent"; // Type: fixed_cart, percent, fixed_product, percent_product

  $coupon = array(
    'post_title' => $coupon_code,
    'post_content' => '',
    'post_status' => 'publish',
    'post_author' => 1,
    'post_type' => 'shop_coupon'
  );

  $new_coupon_id = wp_insert_post($coupon);
  //$exclude_products = array('61707', '61688', '61684', '61679', '61399');

  // Add meta
  update_post_meta($new_coupon_id, 'discount_type', $discount_type);
  update_post_meta($new_coupon_id, 'coupon_amount', $amount);
  update_post_meta($new_coupon_id, 'individual_use', 'yes');
  update_post_meta($new_coupon_id, 'product_ids', '');
  update_post_meta($new_coupon_id, 'exclude_product_ids', '61707, 61688, 61684, 61679, 61399');
  update_post_meta($new_coupon_id, 'usage_limit', '1');
  update_post_meta($new_coupon_id, 'expiry_date', '');
  update_post_meta($new_coupon_id, 'apply_before_tax', 'yes');
  update_post_meta($new_coupon_id, 'free_shipping', 'no');

  return "ok";
}