$amount_due = 1000;
$amount_paid_so_far = 500;

if ($amount_due == $amount_paid_so_far) {
return “Paid”;
} elseif ($amount_due > $amount_paid_so_far) {
return “Partially Paid”;
} elseif ($amount_paid_so_far == 0) {
return “Not Paid”;
} elseif ($amount_due < $amount_paid_so_far) {
return "Paid + Balance";
} else {
return "";
}