Joe bought a car from Harry's Fine Car Lot and owed him $5000 on the deal, which he was paying back at $500 a month under a Security Agreement. Harry assigned that Security Agreement to Ace Finance Company, and they served notice on Joe that he was to make his payments in future to them. Joe knew, however, that his deal was with Harry, and he ignored the notification and continued to make the payments to Harry. What danger does he face in these circumstances? HI B E CO