Advice on Disciplinary Hearing

[Coconutty]

I am due for a disciplinary hearing next week. The matter should have ended at investigation stage as the complaint (by someone new to the company and holds a high position) lodged against me was due to a misunderstanding on numbers that I generated in a project work. The complainant mistakenly took the numbers to her superior for a decision making process (I have never said that the number was final - I have supplied all the emails proving this at the investigation meetings). She then complained of my quality of work and said that I was dishonest. At the end of the investigation, the company decided to take me to a disciplinary hearing for my quality of work and dropped the initial allegation of dishonesty. The HR did not provide me with a written disciplinary procedure despite being asked and only referred me to the company's handbook. The handbook's procedure on disciplinary proceeding is only applicable (this is clearly stated) to misconduct and for other matters including poor performance, reference should be made to the appropriate policy or procedure. I feel that I am being treated unfairly and I feel bullied and victimised as the complainant, being so high up could have resolved this issue through around the table discussion between all parties involved. This has an adverse impact on my well being as I have been under a lot of stress.

I would like to seek for an advice with regards to the disciplinary proceeding - on the do's and don'ts, what I should ask and what I should be informed at the proceeding or any other advice and perspective. I thank you in advance for your input.