We Buy Cars - Faulty car

I bought a car at We buy cars Joburg South branch on the 24th of May to Scott Scot Pegeout 107 Urban. The first 2 week the car was fine I didn't have any problems, however on the third week I started experiencing issues with the car, there was a strange noise coming from the car like a whistle, the gears are too stiff not only that the car started shaking to a point where the car couldn't start and I got stuck on my way home from work around 2am in the morning. I reported the issue to Scott and he said he was going to lodge a complaint, a week passed by without receiving any response from them I called Scott and he said I should call customer service. I told them my issue and the lady I was talking to asked what was my desired outcome and I told her I like the car but I'm not happy with the issues I've been experiencing with the car and I would like to change it because I need a car and I work night shifts. The lady sent me a list of all the RMI approved workshops and she said I must take my car there to be diagnosed which I did and the workshop sent We Buy Cars a quotation. I called We Buy Cars asking if they have received a quotation and they said they did however they will not pay the full amount they can only pay half and I'll have to pay another half. I was surprised because their agent didn't tell me that there were issues with the car because he showed me a Dekra report and said everything was fine.
A week after I called them I received an email stating that ''they're not going to give me another car or change it because I had test driven the car and I saw which condition it was in and I took it'' however I didn't know the car was going to give me such issues. I knew I was buying a used car but I wasn't expecting the car to give me such issues within a month. I'm extremely sad because I need a car and I work night shift, I can't get stuck on the road around 2am as a woman it's not safe and I fear for my life. I feel I was taken advantage of because I was alone when buying the car and I'm a woman.