Uviva oven Burns food from day one

A bit more than a month ago, my mom purchased a Univa U336 Oven, hob combo from Incredible Connections at Greenstone mall. We have not once been able to use the oven properly as it burns the food. Set it to 70 and the temperature shoots to over 150, 180 and it shoots to over 200 A technician was at our home and confirmed that the thermostat has a problem. He will get parts and come fix it and he has never to be seen again. In such a way that I feel like I might need to open a missing person case. My mom decides to phone Univa and the Customer Services tells her that the technician said their is nothing wring with the oven at all which is clearly not true. Could someone please let me know what I can do as this seems like a violation of the Consumer Protection Act.