Small changes to int billing email layout

Layout/default/Emailtemplates/order/int_billing_info.php

@@ -23,8 +23,12 @@
                     .$order->owner->customer_number." - "
                     .str_replace("\n", "", str_replace("\r\n", " ", $order->owner->getCompanyOrName()));
   */
-  $subject .= $order->terminations[0]->building->network->name." - "
-                    .$order->owner->customer_number." - "
+  
+  if(is_array($order->terminations) && count($order->terminations)) {
+    $subject .= $order->terminations[0]->building->network->name." - ";
+  }
+  
+  $subject .= $order->owner->customer_number." - "
               .str_replace("\n", "", str_replace("\r\n", " ", $order->owner->getCompanyOrName()));
   
   $this->setReturnValue([