Impossible to close a popup (tested with many Windows PC and other android devices)

Impossible to close a popup (tested with many Windows PC and other android devices)

Dear jQuery from experts these dayes I bought a service called LeadTarget Pro :

It works this way :

I create a pop-up in this website using a simple interface : leadtarget.io

the very first time I install the provided plugin in my wordpress website and using that plugin I copy-paste the script generated by the www.leadtarget.io account into my website (choosing in what pages I want the popup to be shown)

THIS IS THE CODE THAT I COPY-PASTE , BUT POPUPS NEVER CLOSE!!

<script type='text/javascript'>
  jQuery(function(jQuery){
    var heading_var_val = 'nillbtesanata2016';
    var cta_var_val = 'nillbtesanata2016';
    var f = jQuery('<iframe />');
    f.attr('src', ' https://leadtarget.io/popup/open/1922?heading_var_val='+heading_var_val+'&cta_var_val='+cta_var_val);
    f.attr('id', '_popupFrame');
    f.css({border: '0 none',height: '100%',left: '0',margin: 'auto',position: 'fixed',right: 0,top: 0,width: '50%','z-index':'99999'});
    jQuery(window).load(function() {
          jQuery('body').append(f);
        });
  });
 
  var receiveMessage = function(event) {
    if ('close-iframe' == event.data) {
      jQuery('#_popupFrame').remove();
    }
  }
  window.addEventListener('message', receiveMessage, false);
</script>


The service support does not help me....I'm very angry! please help me....