Company denies Last month's Salary on Quitting

I was working in a software firm. The company is run by two engineers. I am the only appointed staff, designated as Programmer. One among the engineer is the Sr.Programmer. I was a fresher when I joined there and I worked there for 2.8 years.

Due to some unfavorable health conditions I was absent from 22 Dec to 22 Jan and was undergoing treatment. On 22nd Jan I decided to quit the job and approached them demanding experience certificate.

They demanded resignation letter but I refused as they haven’t issued any appointment letter. After some arguments they agreed to send me Experience Certificate by post. Last day I received the Experience Certificate by Registered post with acknowledgement but they denied paying me salary for the days I worked in December.
I want to know how to deal with them to get my last Salary, which I don’t want to lose. Company neither maintains attendance register nor pay slip. All payments were given by hand except a few months, which were transferred to my bank account.
Please help to get me out of this ordeal.
4th February 2018 From India, undefined

Suppose the entire version of the episode narrated by you is true, perhaps both the promoters of the business venture prefer to be mere technocrats rather than law-abiding employers. Otherwise, they would not have insisted on your resignation letter when they did not issue any appointment orders at all. They might've been inadequately advised by some one that a resignation would be effective only when the resignee fulfills the notice conditions. That's why the denial of the salary for the last spell actually worked. Since the very appointment is unconditional, so must be the resignation. Send a notice to them to disburse your salary forthwith for the days you worked in the last month failing which you will have to approach the Labor Officer for the area for recovery of the same.
4th February 2018 From India, Salem

Uma Sir,
Will labour officer interfere with case of a Programmer?
Is he a worker category?
The gentleman may even have problems proving his employment period.
His only proof of being employee is Experience certificate.
4th February 2018 From India, Pune

Dear Mr.Rao,
IT and ITES establishments come under the respective State Shops and Establishments Act. Unless and otherwise any job position is exclusively exempted, all other persons employed therein are employees under the Act only. Since the questioner was employed as a programmer in the establishment, he also becomes a workman under the ID Act,1947. As you are aware, complaints of non-payment of salary, though they have different modes of remedies under the same ID Act as well as the Payment of wages Act,1936, are settled mutually before the Labor Officers since it is quite informal, inexpensive and less time-consuming. Crediting of salary for some months in his Bank a/c and the experience certificate issued are sufficient proof of the poster's employment in the establishment.
4th February 2018 From India, Salem

The only case for not giving the salary would be the Notice period. And what is the relieving date as per exp letter.
5th February 2018 From India, Hyderabad

Dear Mr. Umakanthan Sir,
Kindly clarify the word 'Notice' in #2 refers to a legal notice send through an advocate or a Personal one from my side in the matter concerned. If it's a personal one, please give me idea about its format, if any. Please understand that my doubt is due to my lack of knowledge in such proceedings.
5th February 2018 From India, undefined

Dear friend,
" Notice " here does not refer to a legal notice. It is the intention of the employee or the employer to terminate the contract of employment effective from such and such date as stipulated in the contract of employment or the service regulations of the establishment that would form part and parcel of the contract. If the employee wants to resign on X date, he has to mention specifically in the resignation letter that he would serve the notice period of Y days stipulated or he should pay the salary equivalent to Y days on acceptance of resignation. Similarly, if the employer wants to terminate the services of the employee as per the contract on X date, he should do so only after the expiry of Y days or he should pay salary for Y days forthwith and terminate the employee.
5th February 2018 From India, Salem