Serve 3 months of notice period

Hello, I have put my resignation letter on 28th may 2021 in my current company, i have already completed around 1 month of notice period, now when i am asking for early relieve because of the opportunity in other organisation where my joining is on 28th june 2021, my current company is not releasing me by saying we have commitments of jobs, when i am ready to buyout the remaining notice period even then they are not agreeing. Also it is stated in my employment agreement Three month's notice shall be required in the event you decide to leave the employment of the company or the company decision to terminate your services or salary in lieu thereof on either side. in case of waiver of notice period from your end, you shall be liable to pay the company three months salary as per the last drawn pay slip as well as waive off encashment of leaves. however, the company has sole discretion to waive payment of salary in lieu of your notice period depending on the circumstances. Please suggest me how can i proceed as i don't want to miss the opportunity from the other organisation.