My question is, does this law apply to private companies? (Vodafone India shared services pvt ltd)
This law is applicable to private companies too. Nobody is exempt from labor laws.
If the company is arbitrarily doing this, you may first make a representation seeking relief of 50%salary after deducting 50% towards the advance amount paid to you, if the company is not acceding to your request/representation, you may issue a legal notice but for that you have to be prepared for the consequences the company may plan to initiate against you in retaliation.
Conslt a labor law practicing lawyer in the local and proceed as per his advise on all such further issues.