Gratuity Issue

I had been employed at a private engineering college in Kolkata without any break for a period of 11 years and 3 months. However, when I resigned from my position in August 2018, I did not claim my gratuity. At the time, I was under the impression that my organization did not provide gratuity benefits to its employees. Recently, I discovered that it is mandatory for all organizations to pay gratuity to employees who have worked continuously for more than 5 years. As a result, I sent an email to the accounts department and principal of the college requesting my gratuity. I also sent a hard copy through the post, although I do not have proof of this. Unfortunately, I did not receive a response to my request. When I followed up with the principal over the phone, he informed me that the organization does not pay gratuity. It has now been almost 5 years since I left my position. My question is whether it is still possible for me to claim my gratuity, and if so, how would I go about doing so? Additionally, would your organization be able to assist me in this matter, and I am willing to pay any professional fees associated with your services.