a lot of people do this. they complete a fanfic on a site like this, and everyone has read the whole thing for free. then they go and publish the book and start selling while their fanfic is still up for everyone to read for free which is stupid as , why are you selling your book if everyone can read it for free anyway? take down the story if you plan on selling it. and just fyi publishes can and have the right to press charges on you yes you the writer, for distributing the story for free. 

it's either leave to story free to read and don't publish and sell a hard copy. 

or

take down the story if you plan on selling it.

or

don't post the story up for everyone to read freely at all in the first place and simply just publish and sell.