Get it acknowledged by HR and your immediate boss.
There are many threads about effect of breaking bonds,amount which can be charged by company and circumstances where they charge etc.Use search button of the forum and get lot of information.
Nothing to be worried.I am sure soon you will join VSSC.
17th July 2015 From India, Pune
5th August 2015 From India, Chennai
Have you given notice as per offer letter?
Your threat to go to police and labour authority will make the company return your certificates.
Politely discuss with them this matter.
These kind of bonds have no real legal force unless and until they have given some quantifiable training and incurred training expenses on you.
Polite but firm attitude must be shown to insist on return of certificate and balance of salary.
6th August 2015 From India, Pune