The enactments that are applicable to establishment/employer/employee shall prevail upon any private agreement/rule etc drafted by employer and signed with employee e.g. appointment letter/FnF policy/HR policy/service agreement etc......................and such private agreement/rule etc may not be worth the piece of papaer onw hich it is written.
It shall be certainly appropriate if instead of generic advise you prefer a considered opinion after due examination of all docs on record and inputs.
Find a very able counsel specializing in Labor/Service Matters and spend quality time with your counsel.
The FnF wages should be paid on LWD or say within next 3 days or max. by usual/fixed/applicable pay day.
The unpaid wages are debt on employer!
You may demand to supply acknowledgment and acceptance of notice and final resignation, Correct FnF statement, salary slip of all months, Form16 as per correct FnF statement, PF a/c slips of all years, ESIC card, acknowledgment of handover of assets and charge,NOC/NDC...........