You should write a letter to the company, mentioning your designation, duration, and general duties, stating that you have worked with them for more than five years and politely request them to pay you the gratuity amount. Most probably, they will not reply. Wait for about two weeks and send them another letter politely reminding them about your gratuity payment; do mention or reference your first request as well.
Both letters should be sent by registered post acknowledgment due (registered AD). When the letter is delivered, the postman will take an acknowledgment from your company that they received your letter, and this acknowledgment will be delivered back to you by the post office. Keep both the acknowledgments and photocopies of the letters with you; you will require these later on.
Scenario 1
If the company does not respond to you, then take your appointment letter, pay-slips, copies of the letters, and AD receipt and go to the labor officer and register a complaint.
Scenario 2
If the company responds to you in writing that they are not covered under the Gratuity Act and refuse to pay gratuity, then take the company's reply, your appointment letter, pay-slips, copies of the letters, and AD receipt and go to the labor officer and register a complaint.
As per law, if you are eligible for gratuity, the company has to pay gratuity to you automatically, i.e., you do not need to make any request or application for it. However, to make your case stronger, you should show that you made polite requests, but still, the company is not paying you gratuity in violation of the Gratuity Act.
Non-payment of gratuity is a serious offense; the labor officer will take strict action, but you need to be a little patient and calm as these matters take time.
In my experience, some companies do take advantage of naive/unsuspecting employees, but once they get a notice from the labor office, they immediately clean up their act and settle all claims/dues as per law.
Hope this helps.
Best Regards,
Ritesh Shah