Arbitrary bond on joining letter in my first company.

In my first company, I resigned in 2016. My offer letter involves a 3L bond for 2 years. i.e. If I want to leave the company within 2 years, I have to pay 3Lakhs. But I resigned after the completion of 1st year. That time I had a conversation with my manager and HR. It was mentioned that the bond amount is because of the training company provides—there were flaws in the bond. For me it was 3L and for others it was 2L. I was not provided with any kind of special training. I was trained along with others. But they didn't agree. During selection too, they didn't inform me about the kind of work, they will allocate me. I was interviewed on C language, but I was forced to work on AS400. I was given only a week's time to decide after joining in the office. On these lines, I told them the bond was arbitrary and forcing a bond on new entrants was not ethical. Negotiations had not happened properly. So I left but I served almost 1.5 months after my resignation and even supported the team remotely on my old job tickets. So It is not because of not reporting to work, it is because of the bond I had absconded my job. As I have no other option. they served a show cause notice (not from any court just from an unofficial and from the company side). I didn't reply/ So is it legal, to have such kinds of bonds in India? For me, it's a kind of slavery. Forcefully retaining me for the job I was not informed about and I didn't like. Is there any possibility to get my relieving letter now, as my new employer is insisting on it? Will it affect my career in private jobs? feeling like it's a violation of my Fundamental right - A.21 (Right to life and Liberty). Thanks in advance.