Company terminated by giving inappropriate reasons

Your employment with a private company is governed by the letter of appointment issued to your by the company and comes under the ambit of Contract Act and terms of the termination of the employments depends on the condition mentioned in the employment contract. Yes you are eligible for gratuity. Issue a legal notice first demanding the same.  You can file claim before the Controlling Authority under the Payment of Gratuity Act within the area, your employer’s establishment is situated or where you were working at the time of termination.