Wrong Purchase, Difficult Exhange @ Reddy's Metal Worx

On September 18, 2024, I paid R4500 for a steering rack from Reddy's Metal Worx for my Nissan Qashqai Visia. The shipping fee was R200. First of all, I was rushed into purchasing the component and was provided pictures to confirm that it was the right one. I informed them that I wasn't sure and that I needed to decide and pay right away. They assured me they will exchange the part if it turns out to be incorrect. Thus, the component was shipped. It was the incorrect one when I brought it to the repair. The mechanic went to the nearby parts store and got the correct one, which he purchased for R1600 plus three wipers. I turned around. On September 20, I returned to Reddy's Metal Worx and informed them that the steering rack was incorrect. I asked to return the incorrect one and receive a refund, but they reminded me that I couldn't and that they could exchange it for the correct one instead. Since we were corresponding on WhatsApp, I sent them the proper one as per our agreement. I would repeatedly ask, and they would promise to get back to me. Finally, on September 26, they did, and they informed me that the proper part was R6100, and I needed to pay R1600. I informed them that I had paid R1600 for the fixed part and that they were being unjust to me. After that, they consented to give me the right part. Nobody has been in touch with me since I last spoke with the salesperson on the 26th at around 16:30.