I have tried
<?php if((isset($_POST['cs_approved']) && $_POST['cs_approved'] =="1") && (isset($_POST['cs_completed']) && $_POST['cs_completed'] =="0")) { ?>
to send the Approved email, however this doesn't work.
I have used
<?php if((isset($_POST['cs_approved']) && $_POST['cs_approved'] =="1") && (isset($_POST['cs_completed']) && $_POST['cs_completed'] =="1")) { ?>
To send the Completed email which works fine.