Complaint against a store manager

My mom bought a washing machine from OK Furniture (Phola mall) on the 25th of February, the machine got damaged 3 times now, and we had technicians coming to fix it without success. Today she went to the store advising them to fix or replace it since it is under warranty and guarantee. Nondumiso Mahlangu (store manager) was very mean and not willing to assist her, she rudely said that they are even doing us a favour by fixing the machine. Unfortunately, we had a very bad experience and no customer satisfaction was fulfilled, kindly train your staff with communicating with customers and how to treat them during such incidents.