Microwave exchange complaint

We went to the Shoprite at Shoprite Park in Parow to exchange a microwave that was not working anymore but was within the warranty period. Had it taken into the store and the store, after a while, said that they cannot take the product to exchange as there was only 2 weeks left on the warranty (there is actually a month and 3 days left on the warranty) and was mentioned by the Branch Manager Sharon that they need to contact the buyer or Head Office to see if they can exchange the product. I contacted the Shoprite call center and explained that I used the microwave the night before and it worked perfectly but the next morning it was not working, we had no power outage, no load shedding , where they emailed the email from the buyer or Head Office and we were told that the product cannot be exchanged due to "the product was utilized outside the bounds of our exchange or refund policy and thus, unfortunately, we cannot offer a refund or exchange", two completely different reasons as to why they cannot exchange the microwave. I advised the call center agent that I would like the email that the branch manager sent to the buyer or Head Office in order to have a recount of what the store mentioned, but that was not sent to me. I contacted the customer care line again to find out what the real reason is as to why the product cannot be exchanged and today the agent said that upon in store inspection, the microwave had rust inside hence why they cannot exchange it, however that was not mentioned to us in store, not mentioned to us about the in store inspection. The microwave had not been opened or was not tampered with in any way and yet they could say that there was rust inside. In store, we were only told that they took pictures of the product. Checking inside the microwave, there is no rust whatsoever so I do not understand how it is possible that it could be the reason. I do not want to speculate as to why they could not process the exchange, but the first reason provided could be the actual reason as to why they do not want to have the product exchanged. The product was purchased on 20 August 2023, meaning the product is still under warranty.