Gratuity Denied by Employers - have completed 20 years of service - employer saying below the required numbers

My employer denies to pay gratuity saying that the required number of coming under the purview of the payment of gratuity act 1972 much below the required numbers. I have completed 20 years of service. I have submitted From N to the labour Commissioner but today at the time of hearing my employer file above mentioned reply to the labour Commissioner. Although in my offer letter it was mentioned that you will be entitled of Gratuity.
Now what to I do or reply, kindly suggest.

Hi, If you have completed the qualifying continuous service period under the Act then you will get verdict in favour of you. As the case is before the ACL Chamber please wait for the final verdict

Madam,
What was the type of establishment you had worked - a factory or shop or any other type of establishment? If it was a factory, mine, oilfield or a railway company no necessity for the minimum no of employees and the no comes into play when it is a shop or establishment only. Even in such case it is enough that once the no was 10 or more. You had put in a continuous service of 20 years in the establishment. As such had you ever noticed when the establishment had 10 or more employees. If so ask the CA to direct the employer to produce documents such as attendance register, wages register of employees pertaining to that particular year. Otherwise, you have to argue your case as the liability to pay becomes a contractual liability based on the condition mentioned in the offer/appointment letter only.

Hi
Umakanthan.M
Thanks for the advice, my previous company comes under Shop and Establishment Act. So far my knowledge Previously its maintain the notice and renewed but last 10 to 12 years it's not maintain so far my knowledge.
They doing wholesale of Foreign Liquors in entire part of West Bengal. I don't know does my previous co comes under shop and Establishment or not.
And the employees part they always maintain below 10 as they splitting the employees in a various other's non operating companies. Our number of staff any moment not less than 50 includes daily loaders ( Their payments settlled in cash as delivery charges ) and other staff like sales / Administration/ accounts was splited different companies.
Although my previous employer settled gratuity other staff also in tenure of service, but recently they closed the core business due to some government policies, employer denies to pay gratuity.
Regards
SUBRATA BHOWMIK