@ Sk.Jafar Ali,
Submit FormI under proper acknowledgment to contractor and if the need be Principle Employer as well.
Let there be a written reply from employer to you.
1. Until exempted the Act may apply to society.
You may pick up relevant points from such threads e.g; illustrated threads at:
https://www.lawyersclubindia.com/experts/Payment-of-Gratuity-600816.asp
2. It there is no break in continous service then Gratuity may be payable.
If the break is artificial so as to avoid payment of Gratuity, you may still succeed.
3. You may make it crystal clear that your association was as per 'Contract of Service' or 'Contract for service'.
In certain situations if Contractor does not pay it might be possible to fasten the liablity on Principle Employer.
You may pick up relevant points from such threads e.g; illustrated threasd at:
https://www.lawyersclubindia.com/forum/whether-gratuity-payable-to-contract-employees-6439.asp