public async Task <IActionResult> DeleteMailingAsync(int id)
        {
            try
            {
                await _service.DeleteMailingAsync(id);

                return(NoContent());
            }
            catch (ExceptionTypes.MailingNotExistException er)
            {
                return(NotFound(er.StackTrace));
            }
            catch (Exception er)
            {
                return(BadRequest(er.StackTrace));
            }
        }