Makro supp**** and incorrect heater

The heater I purchased from Makro was delivered incorrectly by their supplier. They are telling me that they only offer refunds, which could take seven to fourteen working days, now that I'm attempting to return it for the correct one. First of all, it is not my fault that the supplier sent the incorrect item. I asked them to get in touch with the supplier and ask them to deliver the correct item and pick up the incorrect one, but they told me they couldn't. The supplier will then have to pick up the incorrect item before they can start the refund process, so I should be the one inconvenienced by their supplier in this cold.