Gratuity matter for trainee employee

Dear Sir,
I worked in Private Limited company from 21.12.2012 to 12-05-2018. i also got my salary direct by RTGS/NEFT in salary account(which opened by company for me in March 2013.) in HDFC Bank. now after resigned i asked for Gratuity to company HR, but he denied my request by saying that i am on payroll as a trainee in company till March 2014 after they place me on roll in company so company not pay my gratuity amount. i asked to give appointment letter copy with my signatured where mentioned that i am on payroll base or as a trainee but HR not give to me till time. i have not joined as a trainee or payroll, request to you pl help me. what should i do in this matter. is there any other way to explain to company's HR or any legal action suggested for me to take.
Regards,
Rohit Gohel

Dear Rohit,
Designation can not be a conclusive proof of a person's employment status. No employee could be a trainee for almost 15 consecutive months in an organization unless and otherwise he was recruited only as a trainee under a scheme of training with stipend. Therefore, notwithstanding the nomenclature as trainee in the company records, such a person would be an " employee " as defined under the Payment of Gratuity Act,1972. Better engage the services of an advocate and file a claim for gratuity before the Controlling Authority under the Act.

Thank you very much sir, for your guidance.
Regards,
Rohit Gohel.