i worked for a company for 3 months under probation during which two of my reporting managers misbehaved with me and were partial against me in terms of performance review. There is enough evidence of abusive texts over Whatsapp and non-cooperation in general. Based on a review meeting in which the two RMs and two HRs were present, my managers noted that my performance was unsatisfactory on the job and have also alleged that i consumed illegal (narcotic) substances which have jeopardized the safety of fellow teammates, which is a lie. They have not given any solid evidence of the same and have themselves admitted that they do not have any concrete proof to base their claims. Even then, based on these outputs, the HR team decided to not go ahead with keeping me as a permanent employee and asked me to resign from the job. I forcefully did but the next day also wrote a complaint to the HR about my manager's bias, attaching screenshots of abusive language on whatsapp that he sent me and also complained about defamation that led to a biased review. HR has however not considered this and is still accepting my Manager's review as true, giving all sorts of excuses. I have also given a complaint to the Disciplinary Action Committee of the company.
Should i file a defamation complaint as it caused damage to personal and professional reputation and led to loss of livelihood? What is the right course of action ? please help