Separation policy

I was working as HOD in An Institute.I resigned my job by serving only 1 month notice period.I did not served 2 months notice period for which i paid my 2 months salary to them.though it was NOT mentioned in my offer letter that i have to pay.They blocked my two months salary.Now again they are asking me to pay 50000 more.My main concern are:1.They showed me Separation policy(signed by me) but that is not given in my offer letter.Is it legally right to keep the separation policy with them? 2.After resignation, when I was constantly asking for the rules of settlement no one told me about the policy.Instead they started harassing me mentally.I left 0n 15 Oct 2015, and they are sending the FnF on 16 Jan 2015.I have been waiting for my exp.Certificate. 3.PF and TDS payments are not clear and no evidences are there with them. please help me to understand that is it the right of employee to have one copy of separation policy or not? if i dont have the copy and the HR did not tell me about the policy before leaving,shouldn't it is a cheating? They took 90 days to Complete FnF,and in letter it is given 45 days. They are not giving justification about my TDS and PF deducted. They are charging 14.5% tax on notice period. Is all are correct? please answer me.