New Hyundai I10 door mechanical fault

After purchasing a brand new Hyundai on the 29 September the driver door stopped opening from the outside within 3 days and was reported. Instead of changing the car I was told they must fix it and they will book for me. Till today no help. I keep calling no assistance because they cashed in and they don’t care. What a painful experience. How do I start fixing within 3 days. You must collect your ******* and give me a new car, it’s your mechanical fault not mine. I tried reaching out but your customer service is just next to none. I bought this car at your dealership in Springs.