82 yrs old granny treated unfairly by Defy and OK furnitures

My granny who is 82 bought a defy stove 2 months ago from OK furniture at Chris Hani Mall in Vosloorus and the stove is not functional. She can't bake. The technician who came to assist a month ago made it worse. Now she is been send from pillar to post. OK says the matter is referred to defy and still nobody is assisting her. The service that is given to our elderly citizen is shocking. If the matter is not deal th with, I will take the stove back on Wednesday and demand a full refund.