codeigniter flashdata not working as expected

I have set flashdata in controller like

public function customer() {
    $data['title'] = 'Black List Management';

    if ($this->input->post('single_black')) {
        //echo 'here';return;
        $wallet = trim($this->input->post('single_wallet', TRUE));
        $reason = trim($this->input->post('reason', TRUE));
        $match = preg_match('/^01[15-9]\d{8}$/', $wallet);

       //if not valid mobile
        if ($match == 0 || !$match) {

            $this->session->set_flashdata('message', 'The wallet is not valid Mobile no.');
            redirect('blacklist/index');
        }
        $is_blacklisted = $this->db->where('wallet', $wallet)->where('is_blacklisted', 1)->get('customers')->num_rows();

       //if already blacklisted
        if ($is_blacklisted > 0) {

            $this->session->set_flashdata('message', 'This wallet is already in blacklist');
            redirect('blacklist/index');
        }

        $this->form_validation->set_rules('reason', 'Reason', 'required');
        if ($this->form_validation->run() == FALSE) {// if invalid form
            $this->nuts_lib->view_loader('user', 'blacklist', $data);
            return;
        } else {
            $user_id = (int) $this->session->user_id;

            $query = $this->db->where('wallet', $wallet)->where('is_blacklisted', 0)->get('customers');
            $result = $query->result_array();
            if (count($result) > 0) {// if exist uppdate
                $customer_id = (int) $result[0]['id'];
                $blacklist = array(
                    'is_blacklisted' => 1,
                    'blacklist_meta' => date('Y-m-d H:i:s') . '|' . $user_id . '|' . $reason
                );
                $this->db->where('id', $customer_id)->update('customers', $blacklist);
            } else {// insert
                $new_blacklist = array(
                    'wallet' => $wallet,
                    'is_blacklisted' => 1,
                    'blacklist_meta' => date('Y-m-d H:i:s') . '|' . $user_id . '|' . $reason
                );
                $this->db->insert('customers', $new_blacklist);
            }
            $this->session->set_flashdata('message', 'Successfully Blacklisted');
            redirect('blacklist');
        }
    }
}

From this customer method redirecting to following index method when error

public function index() {
    $data['title'] = 'Black List Management';

    $this->nuts_lib->view_loader('user', 'blacklist', $data);
}

In my view file (user/blacklist.php)

$message = $this->session->flashdata('message');
if (isset($message)) {
     echo '<div class="alert alert-info">' . $message . '</div>';
}

So when get $error its showing flashdata nicely, But problem is when get same error next time (after submitting form) then flashdata not show anymore.

What I have tried so far is CodeIgniter flashdata not working after redirect

I need to show flashdata message evry time when get $error

Finally it works after a long effort. All you have to do is use $this->session->keep_flashdata('message') with $this->session->unset_userdata('message')

here is my solution (view file)

    <?php
    $message = $this->session->flashdata('message');
    if (isset($message)) {
        echo '<div class="alert alert-info">' . $message . '</div>';
         $this->session->unset_userdata('message');
    }

    ?>

After that in my controller construct function

 public function __construct() {
    parent::__construct();
    .....
    $this->session->keep_flashdata('message');
}

it works in each error. still have some silly issue but working nicely so far