Employer not releasing from duties in 1 month

Employer not releasing from duties in 1 month. Forcing to serve total 3 months notice. I am ready to buyout the 2months but not allowing to do so. My appointment letter says: The appointment may come to an end at an instance of by either party by giving the other the notice in writing in 3months. Your releiving from the service of the company would be contingent upon the successful completion of the full and complete notice period.failing to do would entitle the company to recover damages for all losses caused due to any shortfall of the serving the complete notice period. The company in addition to its rights to recover damage will not furnish a releiving letter in case of shortfall in the notice period unless such shortfall has been signed off by the appropriate person of the company. I. Ezceptional situations the company reserves the right to waive off notice period at its sole discretion. In case i join another company after 1month notice. What action the present company can take. I have given the resignation and mentioned the reaso. As due to my father's serious illness and submitted sufficient medical documents regarding this. I got a good offer in another company bit they are not Willing to extend joining date