I'm wondering what exactly you mean by saying your dispute was rejected. As far as I know, the only way a video can be taken down again after disputing the automated Content ID is by filing a DMCA notice, in which case there would be a strike against your account. In that case, you should be able to file DMCA counter-notice and get it restored. That might even work if there is no strike, though I'm not completely sure about that. For anyone who wants to know more about fair use and copyright disputes on YouTube, I actually run a website providing tutorials about these issues: http://fairusetube.org