Xtranet Technologies Private Limited - organization not relieving employee

I have worked in an organization Xtranet technologies from July **** to Oct **** .On ** Aug **** , i have sent resignation mail to my HR On ** Aug **** My HR accepted my resignation and confirmed that your last working day will be ** Oct **** as per company policy you have to serve ** days notice period.Then after accepting my resignation ,My HR cancelled my resignation on ** Sept **** asked me to continue your services giving the reason that company will be charged * Lac on your exit from Client (CRIS).When i asked how it is related to me if am following your procedure of exit.My HR forced me to revert my decision and mentally harassed me .Even then also i have not reverted my decision and left the organization after serving notice period of ** days.In the meantime i was continuously asking the proper reason through mail behind rejection of my resignation .But every time they told me to continue your services till our project tenure because we have such contract with the Client (CRIS) .In the mean time they have not given my salary of almost ** days .They denied to relieve at any cost and also denied to give me relieving letter and also harassed me mentally and bullied to ruin my career through negative feedback for future organizations .Worst thing is , now they have given me absconding notice through mail and still harassing me saying they will take legal action against me under IT Act and IPC sections.