@trenbania you’re using the_field('field_name', $p->ID) when you should be using get_field('field_name', $p->ID).
Also, if you read the instructions for Relationship filed, you must call the foreach variable $post in order to override the global post variable. So your foreach loop should be: foreach($posts as $post). Then you have to setup the postdata: setup_postdata($post)
