wrongful termination and defamation

I was terminated on the charge that I deleted logs on the server because I was connected. The charges were based on witness statements . I had an opportunity to inquire questions from the department and had them contradicting themselves where the department once stated I deleted logs because it contained information who deleted the tables. When I showed Oracle workings don't store such kind of information and showed through their own logs (the department provided me those logs), the department changed their statement saying that they never said that. I have all this information in writings from the department. The technical assessment of me deleting the logs is not supported by Microsoft workings. I have the information from Microsoft Tech.