A plumber left the job in the middle, how do I close out the job?
Make sure the plumber does not put a lien on my property for the full price.


Hire a lawyer. 


  Get a refund of the money not used


See the answer to the first one.

Honestly, I'd tell the plumber to consider the payment you gave "paid in full for services rendered" and let it go. Life's too short to deal with shoddy contractors...