Sold me a car under false pretence

I purchased a Renault Kwit at We Buy Cars Dome on 28 July 2023, and collected the same day at 18H30, just after their closing time. Just when left their gates, the engine lite came on. I alerted the sales person, Evans Chabalala immediately, who advised me to take it to the Renault Agent as its still under manufacture warrantee, with full service history

after keeping the car for a week, Renault returned the car saying the engine was opened before so there is no warrantee

We Buy Cars Dome through the sales manager, Oswlad, says they can't help me, and I must write a complain to We Buy Cars Head Office.

I am now stuck with car which I was made to believe it was still under manufacturer's warrantee