The owner of a condominium hired a cleaning and junk removal service to clean his condominium after he moved. The parties agreed in writing that the company was to completely empty out the condominium, wash the walls and floors, and clean the appliances in exchange for $1,500. Shortly after beginning performance, the company assigned to a creditor its right to all monies due under the contract (i. e., $1,500), and the creditor promptly notified the condominium owner of the assignment. The condominium owner acknowledged the assignment. The company continued working, completely emptying out the condominium, washing the walls and floors, and cleaning all of the appliances except for the oven before quitting the job. It would cost $150 to hire a substitute to clean the oven. The condominium owner refuses to pay the creditor anything because of the cleaning service's breach. If the creditor sues the condominium owner, how much, if anything, is the creditor entitled to recover