First Data Global Gateway and Authorize.net

I am having trouble setting up my receipting options with Authorize.net and Global Gateway e4 from First Data. I set everything up according to their installation instructions here:

https://firstdata.zendesk.com/entries/21805968-zencart-integration-instructions

Yesterday I took a pretty large payment from a customer through my Zen Cart store located here:

https://www.Datamancer.com/cart

Everything works and the payment gateway accepted the purchase but none of the data was processed by Zen Cart. I did not get any notification of the order and in my administration there was no order under the customer's name. The order also remained in his shopping cart. I called Global Gateway directly and they said it was something I had to contact Zen Cart about and refused to help me entirely.

They have assured me that Global Gateway is properly sending the post data back to my website so I am assuming it is the Authorize.net module that is improperly configured.

Has anyone had any similar experience with this? Thanks and any help would be appreciated.