What other business operates like this?
Would you go to the store and pay for 3 pair of jeans and only get one and then call every two weeks to find out if they will give you the rest?
Will you go to a restaurant, order food and have them bring you each course every 3 hrs?
Will you pay a shipping company to ship 3 packages for you and only ship one every 2 weeks?
Then why do people play at books that slow-pay?