Exchange of underwarrant item.

I have a problem with makro business, I have a fridge that has stopped working while still under guarantee. I contacted their reps and they sent technician who couldn't fix the fridge. Now the challenge they offering the exchange of a smaller fridge which I'm not happy with. I paid R8499 for the fridge on the 11th february 2018 with a five year guarantee. I'd love to have this matter sorted soon because the arbourtown branch seem to be struggling to help me. Thank you