Not Releasing me

I joined a small organisation and after completion of 1.4 year they ask to signed a contract having some points including notice period extended to 60 days before it was 30 days, but there is caption that "not applicable on continued employment" i signed that document because i think this point will not applicable on me. and now they are not releasing me ,I am ready to serve 30 days notice period, but they are forcing me to serve 60 days notice period, but my new employer want me to join as soon as possible. below are the points on which they are forcing me to serve 60 days notice period, even though i signed this contract before 5 month only. other leave with 30 days notice period, they are just forcing me. so please let me know what i can do. Even they have not gave me any appraisal, i am working on the same salary with what i joined . Probationary Period and Notice Period (Not Applicable as its continued employment): • First six months of the employment constitutes the probation period. During this time, the Employer and Employee can terminate the employment with two weeks notice. • After successful completion of probation period, the notice period to leave or terminate employment will be 2 months from Employee and Employer.