Gravity Forms / WordPress Endpoint URL

We're using Gravity Forms to set up a donation form for a client and we have everything connected and payments processing fine but we want to make sure the Billing Details are passed to Moneris as well. 

Anyone have experience with this? I understand this falls into 3rd Party software territory but rather than banging my head against the wall further I thought I'd see if anyone has experience with it that would be willing to point me in the right direction.

We're using the following webhook to pass the details but there's a connection missing.

add_action( 'gform_after_submission_4', 'post_to_third_party', 10, 2 );
function post_to_third_party( $entry, $form ) {

$endpoint_url = 'esqa.moneris.com/.../index.php';
$body = array(
'bill_first_name' => rgar( $entry, 'input_2.3' ),
'bill_last_name' => rgar( $entry, 'input_2.6' ),
'bill_phone' => rgar( $entry, 'input_4.4' ),
'bill_address_one' => rgar( $entry, 'input_5.1' ),
'bill_city' => rgar( $entry, 'input_5.3' ),
'bill_state_or_province' => rgar( $entry, 'input_5.4' ),
'bill_postal_code' => rgar( $entry, 'input_5.5' ),
'bill_country' => rgar( $entry, 'input_5.6' ),
'bill_company_name' => rgar( $entry, 'input_27' ),
'email' => rgar( $entry, 'input_3' )
);
GFCommon::log_debug( 'gform_after_submission: body => ' . print_r( $body, true ) );

$response = wp_remote_post( $endpoint_url, array( 'body' => $body ) );
GFCommon::log_debug( 'gform_after_submission: response => ' . print_r( $response, true ) );
}