Similar threads have been started and similar queries have been raised. You should have searched different threads.
Anyway, to answer your question, bonded labor is not legal in India - BONDED LABOR. Service agreements are very much valid. When you are recruited for providing service, they would be providing you some training, and they would charge you the cost of training they are to or already have paid to train you. Apart from that, there are other costs involved while recruiting, i.e., opportunity cost, etc. However, breaking a service bond is synonymous with paying the bond breakage charge.
You need not proceed legally having known the company that you've mentioned (actually which isn't allowed); you can always talk to the HR and negotiate or ask the consequences of bond breakage.
Hope this information helps.