It is legal to have bond for job?

The thing is that in the month of Jan I was placed in a company from my college and I joined them from 1st of Feb. and they asked me to sign a bond on the stamp paper along with they asked me for the cheque of 50,000/- but later on, I came to know that the company is having money problem, they aren't able to afford their employees and also most of the employees are not getting the salaries. Within of week of my joining, I learned that the company is fake actually, they are not giving salaries to the employees and a lot of loopholes are there n their system. They are not having enough projects, so I decided to quit my job as I am a fresher and I don't want any experience letter from their side. I worked for the company from 1st Feb to 29 Feb and afterwards on 15th March I sent a resignation to them stating that my mother is not well and I won't be able to continue, and I also asked them to credit the salary on Feb into my bank account but they didn't pay me anything. Recently I have joined a new company in Bengaluru, and I am very much happy with my new/current employer and here I'm beneficiated by employee benefits. Yesterday I received a mail from the HR that they want documents such as my mother's hospitals documents bills etc. So please tell me what should I do? I have heard from a lot of people that employment bonds are not legal in India so I need not to worry about that as no one can force anyone to work for them or not. I have even stopped the payment on that cheque which I have submitted to that company. Can anyone help me regarding the same please...