Confession statement

My name is Moin Kazi from Jalgaon M.S. I was Sr Clrk in Central Railway. I was allaged to have committed fraud of about 6 lacs. Before departmental enquiry a vigilance inspector called me officially giving a letter & recorded my confession statement. Departmental enquiry was called &I was removed from service. Note that at the time of confession statement recorded none was present & vig. insp. threatened me I don't confess the charges I shall hand you over to Police. Now the case is in CGIT. Management has got no original documents nor original of my Confession statement. They have given the affidavit they destroyed the original record & brought one witness on behalf of Enquiry Officer. My question is that (1) What is legal status of my confession statement in CGIT? (2) In absence of original document used against in DE; what the benefit I could have. in CGIT? (3) How can I prove the confession was recorded under coercion? (4) Note that at the recording vigilance inspector didn't tell that this is voluntary for you & if you confess the charges this confession shall be used you as solid evidence . And none was present there even from my side?