Unfair assessment of Year End appraisal review

I work in one of the biggest BPO's in India as an Assistant Manager. My job responsibility is to check the transactions processed ensuring 99.50% quality is achieved with minimal operational losses. n 12 Aug '15 there was an error which was identified & fixed the following day. My Manager informed me that this was an error which was reported as , " Near Miss " to the client in the database. My Year End appraisal discussion was conducted on 25-Jan-2016, wherein it was communicated to me that because of this incident I was rated as an Inconsistent Performer in 2015. Pls note that in 2015, I checked approx. 17000 applications out of which I had 11 errors for the entire year. Hence, my quality for 2015 stands at 99.93%.Not agreeing with the assessment I have further escalated the matter which is in currently being pursued at a higher level. Hence, I would like to seek my legal options regarding - 1. What are my legal options in case the management decides to rate me as an inconsistent performer ? 2. Is it legally admissible to rate a person inconsistent inspite of achieving the agreed metric/parameter ? 3. Even, if the management decides to change to give me a favorable rating what should the compensation be for the last 30-35 days of mental trauma, agony, pain ? 4. What should I do or what can I do to ensure that there is no retribution from my immediate manager & in case it happens what could be my legal options ?