Otherwise, you can contact OIA if you're in the UK.
My only advice I can give is that verbal promises, phone calls and informal meetings buys you nothing -keep things [email protected] No independent entity I could uncover; very few US institutions have an ombudsman (or equivalent).
Making an appointment and then refusing to meet when you showed up would be weird, but refusing to meet without an appointment would be pretty standard at many places (and there's no obligation for the dean to make an appointment with you if the dean believes longstanding policy would rule out your request)[email protected] Mathematician The dean refused to give me an appointment, in spite of multiple requests via phone, email, and in person (with staff who recognized my name) at the office.
As I mentioned, the dean was new to the position - I'm not sure how familiar he was with policy, long-standing or otherwise.
If you still have any credibility within your university's administration, you could get more traction seeking other forms of redress. This does not mean that your efforts have had no impact.