Issue Regarding Detention Of Salary In The Notice Period

Dear All,
I am working in a reputed IGCSE school, affiliated to university of cambridge. Recently I resigned from the post of a teacher and ready to serve 30 days notice period as per the service rules. However my employer asked me to serve a notice of 90 days as they need to find a new teacher and require that much of time for recruitment. To this I declined as I have to join some other school in the new session. Now my employer has detained my salary of the previous month (a month before notice period), though they already have my security money deposited with them. Please tell me what should I do in this case.

The notice period clause will be triggered by the employment letter read in consonance with the HR manual. No employer can beach the employment terms agreed to by and between the employee and employer. If you find them breaching the employment terms, feel free to write a mail quoting the provisions of employment, warning them of legal recourse in case they do not rectify their error. Give them 7 days time to course correct, under information, failing which file a complaint at 'pgportal.gov.in'.
Best wishes!

Since your notice period was of 30 days, you are not required to serve a single day extra irrespective of whether your school has been able to find your replacement or not.
Non-payment of salary is illegal and attracts interest and penalty.
Simply demand the salary in writing through registered with ad post. Wait for 7-10 days and then you may initiate legal proceedings to recover the salary.

Dear,
Since your appointment letter stated the 30 days Notice period Hence you Need to serve only 30 days Notice and completed the period thereof?
Holding salary and demanding the security amount to retain employees is unfair labour practice. For which employer may be penalise u/s 25U of ID act. 1947.
Send written application with registered post seeking your dues & complying in accordance with the terms of service agreement. If they doesn't proceed according to service condition. Then you can initiate legal action against your employer. And you can evan file the case u/s 33C(2) of ID act. 1947 for recovery of your dues salary if you are categorized u/s 2(S) of ID act. 1947?
Thanks & Regards
V SHAKYA
HR & Labour, Corporate Laws Advisor

Thank you all for replying. Also I need to know what if they hold back my experience certificate?