Tidak insert ke database

Dari kemarin masalah saya nge stuck disini mulu nih kak

semua insert sudah pas letak dan posisinya

<?php
include "config/koneksi.php";

$a = $_POST['nama'];
$b = $_POST['username'];
$c = $_POST['password'];
$d = Member;
$e = $_POST['nomor'];
$f = $_POST['alamat'];
$g = $_POST['email'];
$h = $_POST['facebook'];
$i = $_POST['instagram'];
$j = Suspend;
$k = $date;

if (empty($a) || empty($b) || empty($c) || empty($d) || empty($e) || empty($f) || empty($g) || empty($h) || empty($i) || empty($j))  {
  echo "<script>window.alert('Pastikan semua terisi dengan benar')
  window.location='daftar.php'</script>";



} else {
        session_start();
  $check_user = mysqli_query($conn, "SELECT * FROM member WHERE username='$b'");
	$data_user = mysqli_fetch_assoc($check_user);
   if (mysqli_num_rows($check_user) > 0)
      echo "<script>window.alert('Username telah terpakai')
  window.location='daftar.php'</script>";
 } if (strlen($c) < 5) {
  echo "<script>window.alert('Password minimal 5 karakter.')
  window.location='daftar.php'</script>";


$insert_user = mysqli_query($conn, "INSERT INTO member (nama,username,password,level,nomor,alamat,email,facebook,instagram,status,time) VALUES ('$a','$b','$c','Member','$e','$f','$g','$h','$f','Error','$date')");

    if ($insert_user == true) {
 echo "<script>window.alert('Berhasil, user berhasil ditambahkan. Untuk Aktivasi silahkan hubungi Pengurus')
  window.location='index.php'</script>";
   } else if ($insert_user == false) {
       echo "<script>window.alert('Gagal')
  window.location='daftar.php'</script>";


}
 }
?>

apakah ada yang masih salah kak?

dan ini eror log yang masuk, eror log langsung 2 kak , kenapa yak?

[01-Aug-2019 11:15:54 UTC] PHP Warning:  Use of undefined constant Member - assumed 'Member' (this will throw an Error in a future version of PHP) in /home/asrulzacky1/public_html/member/auth_d.php on line 7

Ini eror log 1 lagi

[01-Aug-2019 11:15:54 UTC] PHP Warning:  Use of undefined constant Suspend - assumed 'Suspend' (this will throw an Error in a future version of PHP) in /home/asrulzacky1/public_html/member/auth_d.php on line 13