Company is not willing to settle the full and final including leave encashment

Hi, I have spend almost 2 years with Frontier Business Systems Pvt Ltd which is a bangalore based company managing my payroll as I was deputed to my client location during this time. My last day of working was 7th December 2018 however Frontier Business Systems Pvt Ltd has not yet settled my FFS which should include the leave encashment amount as well as per the leave policy shared with me. I have sent multiple emails to the HR however there is clear statement made by the HR towards Leave encashment amount which should be a part of FFS. And now they have also stopped responding to my emails. They are not even afraid of legal course of action for which I need assistance if sending the legal notice to Frontier Business Systems Pvt Ltd and then if further required, I will need to file a legal case in Labour court. I would request you to answer below queries : 1) what are charges for sending legal notice. 2) As the company in this case is based out in Bangalore, can we file a legal case in labour court of Delhi. I am looking forward for your kind response in this case. Thanks Vivek +[deleted]