waiting a month for my refund no one ever phones or gets back to me but the supplier has received the return in January already

i bought i portable aircon in January 2025 send it back as it was not what was advertised. The supplier has received the aircon and resold it but Makro still hasn't refunded my money everyday i phone and just one excuse after the other. You can never speak to a manager or supervisor they never available. im thinking of going to open a case of *****. its been a month and mothing is happening