PSU company initially accepted resignation now disciplinary actio

I had resigned from a PSU in year 2009 by just giving 1 week notice ( 3 Months was my notice period). They asked me to pay 2.5 lacs as company policy as mininimum 3 years you have serve ( Not mentioned in appointment letter nor any contract/bond signed) an to pay notice period shortfall. I accepted to pay notice period shortfall but refuse to pay 2.5 lacs as legally not bound to and asked them to adjust with my sixth pay arrears which I was eligible from 2007 ( They refusing to payarrears citing some internal order).They refuse to withdraw my PF. when I contacted PF office they informed that I have not send PF withdrawal form ( Which I had already sent) Then again when I contacted PF office and PSU they immediately issued me Memorandum for absentee ( year 2017) and informed PF office that an enquiry is pending. I have documentary proof as per RTI and lot of communication where they have mentioned that my resignation is accepted and to pay shortfall of notice period. I have replied with all documents against their MOM explaining I cease to be an employee. But, now they have issued a constitution of equiry committee. Please advise my line to action as refuse to accept being an employee now after 8 years of resignation.