I think it's understandable that you would be interested in your file, but I doubt it would accomplish much for you in the long run. They probably don't write down everything that happened in the JC, so there is probably nothing there you don't already know. And even if there was something controversial in there it would be fixed before they released it to you and justified in their minds as "theocratic warfare" I.e. lying and cheating in the name of God.
It's been said by many that a person can be disfellowshipped for anything three elders agree upon and it's true. Justice, fairness and mercy are not highly valued in this religion and many people have been unjustly disfellowshipped. The good thing is that nobody other than Jehovah's Witness care that you were disfellowshipped or why, so it will start to seem less and less important to you as you move on in your life.