We are aware of the judgments and citations have been discussed unlimited number of times in many threads at LCI e.g;
https://www.lawyersclubindia.com/forum/display.asp?cat_id=9&forum_id=49
https://www.lawyersclubindia.com/forum/Clarity-between-gratuity-eligibility-service-5-or-4-8-yrs--28768.asp
.
You alone can and have to find out and mention the 'Gratuity Rules' that apply in your case.
Ask the HR/MD etc to confirm.Also ask if the Compulsory Insurance for Gratuity was obtained from FI say LIC? YOu may also object to false record "myself resigned from company on my own accord.' This record might have been falsified to avoid claim of retrenchment compensation.
The eligibility has to be related to the rules.
If Payment of Gartuity Act,1972 apply, then you are eligible.
Approved leave is counted in service.
Submit FormI and mention that Notice of Determination of Gartuity and Payment has not been supplied. And/or the declinature by email is sufficient to approach against employer for claim of Gratuity, if you are eligible as per applicable rules.
If it is IOCL subsidiary then it may be possible to claim IOCL as Principle Employer.
This IOCL subsidiary seems to have closed only one division i.e. EPC division.
Apparently there was no lay off compensation and attempt to relocate and absorb.
If you are unable to rsolve on your own then, Beyond this you may engage a very able counsel specializing in labor/service matters.