Checkbox Array Value

I am passing my checkbox value to salesforce.com and instead of listing the value it is listing the word Array.

My script based on Alex Hagers script http://www.alexhager.at/how-to-integrate-salesforce-in-contact-form-7/ and works perfectly on all text box fields but my checkbox it not being recorded.

The information is being collected in my WP DB correctly and my emails are displaying the correct value but I cannot get Saleforce to record anything but the word array.

My last modification was to do the following
$newsletter = $cf7->posted_data["Newsletter"];

if ($cf7->posted_data["Newsletter"] == "Yes") {
    $post_items[] = '00NG000000Cbd9t=' . "Yes";
  } else {
	 $post_items[] = '00NG000000Cbd9t=' . "No";
  }

but this still did not work. If anyone has had this issue could you please share what I need to resolve this.

Thank You!

https://ww.wp.xz.cn/plugins/contact-form-7/