Recruited properly but not considered for review promotion

I was duly appointed and promoted four times in the past based on qualifications possessed, and after serving getting four promotions in the past 29 years, I am not being considered for further promotion to Scientist-F based upon the same qualifications on which selection was done initially due to MFSC policy changes which came in Sept 16 but applicable from 1st Jan 2011. I am M.Sc.(Hons. School) in Economics and PG Diploma in Computer Applications and was recruited on these qualifications and promoted four times and no distinction was ever done by the departments to give me projects based upon my qualifications and rather many of my projects developed and implemented are honoured at national and international level. Now the review process has started and screening is going on inquiry from the office, I was informed that my qualification is invalid as per the changes in the MFSC policy which came as rude shock to me. There are around 45 candidates who will be disqualified due to this policy changes. As I understand that the new / updated policy cannot make any reference to the disqualification of already appointed employees for promotion and is always prospective in nature that is for newly recruited employees after the policy came into force. Moreover, any policy changes now could not have ignored employees duly selected in department. In view of above mentioned facts, I request you experts to offer your suggestions how to proceed further. Should I go to CAT and file case single handily or all may go to CAT and file the case collectively. In addition any other advice can be given which results into faster action as the review process has already started. would also like to know is there any judgement by honourable courts in this regard so that case may be filed taking that case as base.