Dear Rashmi,
You have not stated whether the leave was duly granted by the management or not. There is a big difference between an application for leave and the grant of leave.
From your post, it is clear that you applied for leave for 3 months but did not ensure formal approval of leave from the management. Absence without the sanction of leave by the competent authority is considered unauthorized absence and is deemed as indiscipline on the part of the employee, regardless of whether the leave applied for is with or without pay.
If the situation is as I assumed, the management is correct in taking action against you for this misconduct. Just consider, even if your domestic servant is absent for a single day without your permission, you would not tolerate their absence. Here, you have been absent for 2.5 months without leave approval.
In terms of the law, the law would not support you if there is a case of misconduct due to unauthorized absence on your part. The only solution for you is to kindly request the management to forgive you for this instance with the promise to be more careful in the future by not taking leave without proper approval from the management.
Regards.