Employer Threatened of Legal Action for Breaching Service Agreeme

Hi, I was working with an IT company where I signed a service agreement after 3 years of employment for additional 3 years. Due to lack of growth and seniors verbal abuse, I had to request them to relieve me on immediate basis but they didn't relieve me saying that there's no replacement of me! I waited for almost 1 and half month and they hired one senior who would be best for my replacement, so I asked them again to relieve me but instead of that my immediate senior who is also the executive director of the organization verbally abused me and my other fellow team member. After that, I sent them email stating that I wouldn't be able to come to office from DATE. But the HR dept. came and told me that they would take legal action against me as I am under service agreement. They told me to pay 1.5 lakhs and serve two months notice period after it to get smooth relieve. The HR person specifically said that the Court's notice would come! How to deal with this? Do they have rights to send court's notice? Their advocate sent legal notice on their behalf to pay 2.50 lakhs!