Poor service and *******

On the 8th September 2022 on my sona birthday I went to Gadgetime in Tygevalley Mall Cape Town out of desperation as I needed my sons new birthday monitor to connect to his laptop due to the laptop HDMI ports being broken. It was recommended I buy a visual display adoptor. Luckly Gadget time had on of these adoptors. I asked the sales man if is would work on any Laptop and he said yes it will. I explained that the Laptop was an old Acer model and he said it will work. He sold it to me for R699. Whne I came home, the quality of the picture kept flickering and it was very poor. 13 days later, I went back for a refund and they refused. They said they needed to test the item and the I needed to readvthe terms and conditions at the back of the slip. I begged for my money back and told them thatvthe sales man guaranteed it would work. The refused to refund me. The thing is seating in a box and I feel ****** of R699. When I asked all those questions, the salesman was supposed to explan the the terms and conditions. Peter, please help me get my money back