Export DB table to Excel UTF8 problem

Hi everyone,

i have one problem with Export DB table to Excel with UTF8 encoding.

when i add

echo pack(“CCC”,0xef,0xbb,0xbf);

all my columns are in one. Without this command my excel is not in UTF8

function ns_contact_form_csv_pull() {

    
    global $wpdb;

    $table = $wpdb->prefix.'registred_players';// table name
    $file = 'wcgt_prihlaseni_hraci_csv'; // xls file name
    $command = "SELECT * FROM $table ORDER BY kod DESC";
    $nieco = $wpdb->get_results($command);

    $data = array();
    $i = 0;

    foreach($nieco as $zaznam) {
      $i++;
      $data[$i]=array("Meno" => $zaznam->meno, "Priezvisko" => $zaznam->priezvisko, "Domovsky klub" => $zaznam->domovsky_klub);
    }

  function cleanData(&$str)
  {
    $str = preg_replace("/\t/", "\\t", $str);
    $str = preg_replace("/\r?\n/", "\\n", $str);
    if(strstr($str, '"')) $str = '"' . str_replace('"', '""', $str) . '"';
  }

  // file name for download
  $filename = "wcgt_registrovany" . date('Ymd') . ".xls";

  header("Content-Disposition: attachment; filename=\"$filename\"");
  header( "Content-type: application/vnd.ms-excel; charset=UTF-8" );
  echo pack("CCC",0xef,0xbb,0xbf); // WHEN I REMOVED IT UTF-8 WASNT WORK

  $flag = false;
  foreach($data as $row) {
    if(!$flag) {
      // display field/column names as first row
      echo implode("\t", array_keys($row)) . "\n";
      $flag = true;
    }
    array_walk($row, __NAMESPACE__ . '\cleanData');
    echo implode("\t", array_values($row)) . "\n";
  }

  exit;

    }
   add_action('wp_ajax_csv_pull','ns_contact_form_csv_pull');
?>