R90 000 rip off on 2 months

My sister bought a car voetstoot with no disclosed defects, Audi A3, 2007 model in January 2023,for R90 000, which is already a rip off. 3rd day after her purchase the car started having gear disfuntionality. The oil was leaking. The owner of HC Exclusive Motors refered her to his mechanic in Lenz. Who then fixed the engine oil leak. Then the car was ok for a few days until it started leaking water rapidly. Turns out the mechanic of the mentioned dealer was negligent that he didn't fasten the radiator properly it cut the water pipe. They replaced the pipe, this is all happening in the month she purchased the car. Second month the car still bad problems, jerking badly as she drove. She tried negotiaging a refund or another car. The owner doesnt budge. My sisters mistake was to not access the car before purchase. She took the ownes word for true. So ywo months and 1 week my sister is driving that car that breaks evryday and theres nothing she an do about it. Do not buy a car there. You will regret. No customer service or business ethics. Money hungry and ruthless. STAY AWAY. YOU'LL REGRET