Employer not giving Experience and Relieving letter

Hi, Please find the situation depicted below: 1. I was a part of MNC in Pune as Software Engineer and completed 4 years. During my tenure I got many appreciation for my work as my technical skills are good. I have resigned in January because my mother was admitted to Hospital and needs me to take care of her. After resignation in January, I had meeting with HR and she told me that I need to serve 3 months notice period and if I take leaves during the notice period, my notice period will get extended. At that time I was willing to serve the notice period for 3 months. 2. I have taken leaves during notice period in January as well as in February as my mother was admitted to hospital. I got the full salary for January and February despite my leaves. 3. As per last conversation with HR, I came to know that my last day will be on March. At that time, HR did not tell me that I need to pay the money which I got in excess for the month of January and February. So I agreed to leave the company without serving the 3 months notice period. 4. I have initiated clearance on last working day and after that I come to know that I need to pay the money which I received in the month of January and February as I was on leave. HR told me that until the payment, I will not get my Experience letter and Relieving letter. I thought that I was having leaves and due to which I got full salary despite I was on leave. 5. After that I told HR that I can serve the notice period of 3 months as well as the leaves taken by me on notice period. But HR were not agreed to it and said that there is no position for me to take back at work and my ID was terminated. 6. It was mistake by the company that they gave me extra salary despite I was on leave. If there was any mistake in the system then I wanted to correct it on humanitarian ground and I wanted to serve the notice period for the extra payment I got but HR refused it. At any meeting or conversation with HR, I did not ask for early release from the company. Please find the below company policies: 1. As per Company's Policy if the employee have taken leaves during notice period then the notice period will be extended and employee need to serve the extended notice period for the leaves taken by employee. 2. As per Company's Policy if the Employee do not have leave balance then the leaves are treated as Leave Without Pay and the amount will be deducted from the salary. But in my case amount did not deducted from salary and I got full salary which is system's mistake. 3. I did not ask for early release from the Company. As per company's policy if company release the Employee before notice period completion, then Company needs to pay Basic Pay of the remaining days of the notice period to the employee. Here my notice period will be completed after 3 months from date of resignation as well as leaves will be added in the notice period as I have taken leaves during notice period as per Company's Policy. Excerpt of the situation is - I got excess salary from Employer despite my leaves on notice period. I did not know this because I was busy with my mother's hospitalization. On last working day, I came to know that I need to pay the excess amount I received from the Employer then only I will get the Experience and Relieving letter. It was not my fault that I received the excess money. After I come to know that I need to pay money to the Employer that I received mistakenly, I was willing to serve the complete notice period but HR refused it and said my ID was terminated. Can I take legal action on the company, If yes please suggest if I need to go with Labour court or Civil. Could you please help me on this.