Add opacity to the Class "sidebar-nav" and decrease it every day until their menu completely fades away. Set a due date and customize the number of days you offer them until the menu is fully vanished.
Once the menu has vanished a window.alert pop up box will appear that you can put a custom message in. Where the menu once was the message "Disabled. Please speak to site owner" will appear.
/* change these variables as you wish YYYY-MM-DD */
var due_date = new Date('2017-02-27');
var days_deadline = 60;
/* stop changing here *//* Edit the message in between the "" */
window.alert("Pop Up");
/* stop changing here */Just load the not-paid.js file in <head>