Full & final pymt discrepancy and gratuity payment denied

I joined this company in March 2019, since it was a US company but started operations in India the total staff was 7 employees. I worked here for 5.5 yrs and was handling the team, until 06 Aug 2024, they laid me off stating business strategies as the reason. Now they informed me that I can leave the job by giving the resignation same day and would receive the salary for Aug 2024 and on all the documents my last working day would be 31st Aug 2024. So now here are my queries - First query - In my employment letter, it clearly mentions that the employer should pay me one month's gross salary which technically should be until 6th Sep, but they paid me only until 31st Aug. Please correct me if I am wrong. Second query is - The CTC always had a component for Gratuity and they also mentioned that it will be paid as per the Gratuity Act, but now they have denied it saying that we are less than 10 employees and it does not apply to the company, but then why it was a part of the CTC. At the time of leaving I have completed 5.5 yrs with the company and I believe I am entitled to the Gratuity amount. Please help me resolve this.