As far as Vocal Media is concerned, I am clueless Amit like you.

And since you are not a Medium member you cannot read the entire article, nevertheless i can share with the you a friend link here,

https://medium.com/no-time/i-wrote-100-stories-on-vocal-media-then-it-disappeared-with-my-earnings-9fb02aefbe69?sk=9aa86ab4222f8d079322e0b7625c549c

I would suggest you to join some publications and read the guidelines of publications you wish to submit for a better idea.