Defective brakes on new vehicle

Is anybody having issues with the Hyundai i20 braking system. I purchased a new i20 on 9 December 2020 from Hyundai Sherwood, been experiencing issues with the clutch and brake since the second week. I reported this to the salesmen that sold me the vehicle, he told me it can neve be a problem as it is a new car, then boom on the 29 December 2020,my vehicle was parked in my mums yard, hand brake up in gear and it rolled back smashing through the fencing and gate. I called the salesmen immediately and nobody was helpful as they were all on leave. I took my vehicle immediately to Hyundai Pinetown to have it checked, the technician checked the vehicle and showed us a particular way of braking, he referred us to go back the dealership I purchased the vehicle from, however they were not helpful at all. They advised me that they could only help me 4 Jan 2021, when everyone is back at work. I sent them an email and met with them today, however instead of checking the vehicle and sorting my issue and repair, your branches are making me a ****, stating they will not assist me as it is not their problem after a sale as they don't have a service department. I am driving a vehicle with a defective braking system and Hyundai doesn't bother to rectify the issue. Is the service you provide to customers, you will wait for a fatality, rather than rectifying the error. I am being given the run around and you guys are making my life miserable. I am within my rights and 30 day period. I want a full refund and cancelation of the sale or a brand new vehicle. This is the most pathetic service I have received in my entire life. Don't you care what you sell to people. Is the service you provide. I will be going legally if need be me the ombudsman motor vehicle SA. I am being made to run around during Covid-19. Will you pay my medical bills as well, should I be exposed to the virus because of your pathetic service.