K i'm really confused, I'm hoping someone know's what I am talking about

so The Jeena sirf mere liye title song pretty much has her name credited on it, but she's no where to be heard on the cd/tape releases at all, so i'm thinking it's just a typo, BUT

In the movie, it changes from alka to kavita, for one small line....
so what's the deal with this? and is there an actual kavita version out there?