What can I do about falsified documents?

I was recently let go from a due to what was addressed as falsification of a document. I worked as a deputized clerk. Another employee from a completely different department submitted paperwork on a case. The documents had one correct case number and the other had the same case number. Just as I was trained over six years ago I saw the case numbers were the same and had someone look up the correct case number. I wrote the correct case number had it rescanned and sent to the judge. Once the judge received it he made his ruling and sent it back to our office. I am trying to understand how was this document falsified and if it was the entire department has been handling paperwork incorrect for the six years I have been there. Please help. I do not like this accusation and I would like to take it to court if need be.