MAKRO AND CPA

Purchased a 40L Sumsung Microwave oven on 28th May 2024 from Makro Carnival Got it home and the touchpad was faulty. Returned it the same day and was given a replacement. This one had a squeak in the turntable which I though might just go away. However after three weeks used the microwave with a large Corningware dish and some vegetables with a liter of water and the turntable would not turn and a burning smell came out of the bottom of the unit. Packed it up and took it back today, claiming my rights in terms of the CPA as they refused to give me credit without sending it in for assessment to the supplier which could take up too 21 days! after an argument the management agreed to get the unit to the supplier for assessment within 7 days. Their argument is that their invoices specifically state that they can do this even though my reading of the CPA says that the CPA overrides the suppliers own terms. In the meantime we dont have a microwave oven while they "assess" it. The unit was only bought 3 weeks ago and the second of the same model to be faulty!