What are the terms and conditions given in your offer letter / appointment letter. Have the school management mentioned about the security deposit in it. If the same is mentioned, they might have given as returnable deposit or non returnable deposit and some specific period. The PF and ESI Deduction are statutory deduction and you cannot challenge. But the security deposit can be challenged as per the terms and conditions given your appointment letter.
7th October 2013 From India, Kumbakonam