The advice and valuable suggestion of esteemed experts/members is always revered and sought. The valuable advice of learned Mr. Godbole can set the direction for the querist.
The PMO, ministry of finance, etc. have been forwarding applications with comments like that you may get in touch with NIACL which is an independent authority under RTI act.
Although it can be believed thus PMO, ministry of finance, might have kept all docs, supplied by you in their file, they might not act on the same.
Point raised by you includes although investigating agencies like CBI have recommended corruption happened and action should be taken by company, but competent authority has not taken action. CVC has not initiated or concluded. The competent authority in place of initiating and concluding the matter just commented that the matter has been reported to HO and if the HO advices action shall be taken. Whereas the fact is that competent authority is duly empowered to take action. On the top of that as per your posts HO never acted. Evidently the competent authority and HO both have caused willful default.
Therefore a synopsis with relevant points, proofs, documents may be prepared and submitted pointing out that despite having brought all the facts in the knowledge of DGM(P), GM(P), Chairman in person, by emails, letters no one has acted and this is not possible without collusion. Kindly be specific, precise, and avoid emotional outbursts.
At the same time in case of employee who has been whistle blower, the entire corrupt one from top to bottom ganged and inflicted unjustified, most severe, extreme punishments, to keep him out of office.
PM, law minister, home minister has stated time and again that the corrupt and offender should not escape without punishment, and whistle blower should rather be honored. While in your case whistleblower is being victimized, and offenders are making mockery of law. Your fault seems to be that you have lifted the veil.
You have enough reasons to state to PM/President that all the offices made available to public, e.g. PMO, ministry, company and it’s highest and good offices etc have been approached by you time and again and you have exhausted all options before approaching PM/President.
If still nothing happens, a citizen has all the right to declare that the promises made by the highest and good offices are hollow and therefore he can go public, to expose.
This is heartfelt opinion. Kindly do consult your lawyer also.