We Buy Cars dishonest about vehicle condition

Bought my first ever vehicle from We buy Cars. The vehicle was making sounds when we test drove it and according to their mechanics the sound is normal. Unfortunately couldnt drive the vehicle faster than 60kph when purchased on Friday the 19th of March due to Peak Friday afternoon traffic in Capetown. When I eventually had the chance to drive the vehicle faster on Saturday morning, 2e discovered that the engine is completely damaged. We canceled the sale but how is it possible that a company buys a broken vehicle and then sell a broken vehicle? How is it that you do not test drive the vehicle on the highway before selling? I drove all the way from George to buy this vehicle and ended up being a dreadful weekend. We Buy Cars didn't seem too worried about the situation and said just drop the vehicle off in Brackenfell. I received the vehicle in a terrible dirty condition with crumbs and dirt all over the interior. With WeBuyCars, you are just another number and not a valued client. The vehicle I purchased was a 2013 Renault Megane 1.6 dynamique. I suppose they treat you better if you buy a more expensive vehicle? Please assist as to how we can shame them as a company.