that is exactly the level of detail I need to have any idea what to look for, thank you.
On the failure page, add the following code please:
echo("Full Request: ".$_SESSION["WALinkPointAPI_postedValues"]."<br />");
echo("Full Response: ".$_SESSION["WALinkPointAPI"]."<br />");
NOTE: The full request and full response may contain sensitive information, you will need to remove the sensitive information when posting it back.