1.ell,i am sure that this PIL scheme was made in writing when you joined so you can exercise your legitimate right to claim your sahre of PIL. If that is so then the company rightly admitted his liability to make such payment on your resignation . But they have caused now breach of contract by delaying the whole payment.
2. Since you raised the claim at a time when you were active in the company ,your share of PIL for the effort you did at tt time it can never be taken away.The language is importer and hence it is giving rise to the confusion.
3.Since it is considerable delay send them a legal notice one final time claiming your money and if they refuses to pay the money to acknowledge your claim the lodge a criminal complaint of cheating and criminal breach of trust.
4.You can also file a civil suit for recovery of the money.