You shouldn't refuse to pay someone back.
Craig runs a rental car business that has installed kill switches in the cars and owes a large debt on the kill switches.
Craig wants to save money.
Craig pays the company what they are owed and pays it on time.
Craig calls up the kill switch company and says that he is not going to pay the bill.
Craig's business prospers and the threat of the kill switches means fewer delinquent payees.
The company activates all of the kill switches on his cars, temporarily shutting down his business.