public function performDeleteDeassignCrs()
 {
     include_once './Services/Payment/classes/class.ilShopUtils.php';
     if (!isset($_GET['booking_id'])) {
         ilUtil::sendInfo($this->lng->txt('paya_no_booking_id_given'));
         $this->showStatistics();
         return true;
     }
     $this->__initBookingObject();
     $bookings = $this->booking_obj->getBookings();
     $booking = $bookings[(int) $_GET['booking_id']];
     $pobject_data = ilPaymentObject::_getObjectData($booking['pobject_id']);
     ilShopUtils::_deassignPurchasedCourseMemberRole($pobject_data['ref_id'], $booking['customer_id']);
     $this->booking_obj->setBookingId((int) $_GET['booking_id']);
     if (!$this->booking_obj->delete()) {
         die('Error deleting booking');
     }
     ilUtil::sendInfo($this->lng->txt('pay_deleted_booking'));
     $this->showStatistics();
     return true;
 }