Hope you shall take this post in positive spirit.
There are few imp. questions that arise.
You could have consulted elders in the family, competent and experienced well wishers, lawyer/law firm before signing on the dotted line in Bond.
You should have certainly consulted before handing over your original certificates.
Who had advised you to sign on the bond and submit your original certificates?
Has the company asked you in writing to submit certificates and has it issued any acknowledgment for the receipt of certificates?
The original educational certificates can not be asked for, collected, or retained as collateral.
Bond/Service Agreement etc are not illegal.
The conditions in the bond may get termed as arbitrary, unconscionable, unreasonable, illegal, unlawful, void……………………and may become unenforceable.
It should be seen the agreement is in lieu of what favor/expense by the company.
To expect something from employee company has to offer something to employee.
If company has not granted any extra ordinary favor to employee and has not incurred any expense on training that would add to some extra ordinary skills and qualification of employee it may not be able to prove reasonableness of the matter and reasonable amounts if any………………… that company can claim from employee.
You may show the job advertisement, interview call letter, offer letter, selection letter, offer letter, appointment letter, bond, any communication asking you to submit original educational certificates………………to your labor consultant/service lawyer.
The lawyer that has seen all of your docs and has analyzed your inputs can advice you the ebst.
Retention of Certificates has already been declared illegal by judgments of the court of law e.g;
Madras High Court
Dr.S.Rajesh vs The State Of Tamil Nadu on 12 December, 2008
Dated : 12-12-2008
IN the meantime you may go thru the attachments and other similar threads e.g;