Struggling to Get My Relieving Certificates: Can I Fight Back Legally?

I worked for an MNC company for around 4.6 years. I had to serve a 3-month notice period. I requested them to adjust my 45 days of PL against 45 days, and for the remaining 45 days, I would work for the company. They calculated 45 days of PL with the basic salary and confirmed that I had to work for the remaining period. I then agreed to work for one month and pay the remaining amount as notice pay. In this way, I completed my period, quit the company, and joined another company. I paid my notice period amount a few days after my resignation. Now, four months since my resignation, they are still unable to provide me with my experience and relieving certificates. Suddenly, when I called them, they said I have to pay GST on the notice pay amount. I agreed to have it deducted from my bonus. Even after this, they are reluctant to release my certificates.

Experts, please clarify:

1. Can PLs be adjusted with encashment/days?
2. Can I take legal action as they are harassing me?
3. Even after this much time, if they have not relieved me, can I legally fight for them to pay me the Gratuity?

I am not against the company, but people are harassing me and not even providing basic information to ex-employees. Please advise and suggest what is the best course of action I can take?

PL Adjustment During Notice Period

First and foremost, PL can't be adjusted in the notice period. However, you can take encashment against your balance PL.

Legal Grounds and Resignation Process

You cannot go for legal grounds in this matter because when you had given the notice period and expressed your intent to serve the same, the receipt of that letter is itself proof of the same. No need to give or receive any other relieving letter. The date mentioned on the resignation, which you have specified, is your last working day in the company. So please don't worry and carry on with your new assignment.

They have adjusted my PL's with encashment and calculated it based on my basic salary. Even though I have fulfilled all the formalities, why are they not releasing my relieving? Can't we claim for gratuity since I have not been relieved by them as of today.