1. Visit busy Cyber Cafe or Library outside your home town, ensuring that CCTV not present (for the ultra-paranoid amongst you) and that you sign on without having registered or anything like that
2. Set up hotmail account using a made up name
3. Prepare frank and candid e-mail with "feedback" to senior management, copying in whomever you believe would also like to receive management's response (including, potentially, yourself if it assists with the anonymity). Be polite and decent in your e-mail, but assertive in making your points
4. Mention in e-mail that you have such low trust in them that you feel the need to deliver your feedback anonymously, for fear of retribution
5. Review it about 45 times to make sure you can't be identified from it
6. Send and await response.