How to render a field collection?
You may want to have a look how the field_collection module itself renders field collections in the field_collection_field_formatter_view function. I think it's important to note that is uses field_collection_field_get_entity() to load a field collection.

Looking at the code (not tested) I think you can do something like this:

if ($field_collection = field_collection_field_get_entity($line_item-&gt;field_paxsup['und'][0])) {
  return $field_collection-&gt;view('full');
}