please explain briefly. its urgent please

BU4003-G5 Contract Law Practical Application II Jaspreet Singh agreed to paint Sumandeep Singh's house for $1000. Jaspreet painted the house as per the agreement. Jaspreet then assigned the $1000 claim to Harpreet Singh, who served notice on Sumandeep about the assignment. When it came time for payment, Harpreet was informed by Sumandeep that he would not pay because the paint was peeling off his house. Harpreet said that that was nothing to do with him and demanded payment. Explain the legal position of the parties