Do you have an attorney?
Is your arbitration a final employment action? In some arbitration cases the employee must accept the arbitration final decision. You need to read your agreement to see if you can now sue your employer. You maybe limited to bring any information from the arbitration hearing. It appears you need an employment attorney to help you with this process. You may want to employ an expert witness to help with your case to clarify the technical part of your case.
JA restricts the attorneys on this site from accepting clients, therefore I will be unable to help you except in this format. The employment contract may have information that would help determine your options to pursue. Once you review the documentation you maybe able to argue that the arbritrator manifestly disregarded several factor of law. However this is a fact that can challenge the arbitrator and his/her application of the law in the process.
An attorney would need to read what you are saying whereby you were deniied access to the evidence. Recognize that arbitration can bend in the direction of the employer because the employer will have frequency of cases for the arbitrator, therefore the arbitrator want repeated business.
Attorney have challenged these type rulings that are binding , some by suing the American Arbitration Assoc. and several other theories , some successful and some not so. There are several sponsors of a law to discontinue binding aribration but this has not passed, but it has a large following. You may want to contact them.
You are asking is your reason is enough to over come the binding agreement you signed, it will be difficult, but I can not see what you have nor do I know what happen in your arbitration. To tell you something I have not read would clearly mis lead you.
Lawyer
Have 30 years experience in labor/employment law.