Does Makro sell second hand appliances ?

I bought a Samsung Microwave from Makro Polokwane on the 8th of April 2023. I returned the Microwave on the 8th of May 2023 because of an overheating issue and I was told it would be send to be repaired. On the 12th of May I was notified that I would be liable for the repair as the Microwave have been opened previously which led me to believe that i have bought a second hand Microwave as I haven’t opened or tampered with the appliance. Why would I open the faulty appliance if I have only had it for 30 days and have a warranty from the manufacturer ? This is the poorest service I have ever received and is a slap in the face after supporting Makro for a very long time. I will make it my mission to notify everybody on all platforms possible about this as i believe this appliance wasn’t a new appliance when I bought it as it has been opened before.