Eligibility for Gratuity

I joined my company on 26th of November 2014 as a Graduate Engineer Trainee and have been on permanent payroll of the company since then. I am currently serving the notice period and my last working day here is 29th of November 2019. I raised a ticket with my company portal regarding my eligibility for the gratuity amount, and they replied that I will not be eligible for this(I have written communication on this, with the ticket I raised). Few points to note here are: - My probation period lasted for 11 months after joining. - Gratuity deduction started after the same from my salary post probation only. - Since last financial year, Gratuity deduction from my salary has been irregular, as sometimes it hasn't been deducted from there. - No details have been provided by the company on this irregularity explicitly in mail or hard copy document related to this so far. My Queries are as follows: - I need to know if this is fair to do by the company? - If the Gratuity was shown as a part of my CTC for these past years, Should I be getting the deducted amount from my salary on my exit from the company, even if I am not eligible for gratuity? - If I should still be getting the gratuity, which my company is denying of, what action should I be taking for this? Regards, Saurabh