If it is a fed ex issue, add the following code to the failure page to get the full request and full response back from fed ex:
<?php
if(!session_id()) session_start();
echo "<p>FedEX: <br />";
echo "Full Request: ".(isset($_SESSION["WA_Store_Cart_FedEx_FullRequest"])?htmlentities($_SESSION["WA_Store_Cart_FedEx_FullRequest"]):"n/a")."<br />";
echo "Full Response: ".(isset($_SESSION["WA_Store_Cart_FedEx_FullResponse"])?htmlentities($_SESSION["WA_Store_Cart_FedEx_FullResponse"]):"n/a")."<br /></p>";
?>
If it a gateway issue, i will need to know what gateway you are using to give you code for the full request and response from the gateway to troubleshoot.
If you deleted the Featured Pod content tab, you will need to create a new content tab named Featured Pod to get it back.