Resignation not accepted

I'm working as software engineer in a software company from 2 years, while joining the company have written 2.6 years service agreement. There is no proper hike given to me and they are giving more work and cant handle work-life balance here. So decided to move out and got a opportunity from an MNC with 400% increase of my current slary package. So I have went resignation and they are rejecting it because I was in service agreement. It is written in the bond that for breach of contract need to pay some amount of penalty and which will be greater than 2 lakhs. So I told to hr that I will pay the penalty amount but still they are rejecting my resignation request and saying some reason like they have currently less resources and they need me for the project. I requested and even begged them but they are playing with me and taking this as silly matter, kindly guide me sir to tackle this situation. If I god legally then will this issue resolved immediately or will it take years to resolve? If I go legally, and can they put some false cases on me? Because if I have any case on me, then in IT it will be a huge risk and no software company will give job to me and end of my career. Because my offer letter is valid upto oct-10. Kindly guide me sirrrrr, please. I have just 6 months pending in my agreement.