Their business model was to try and build a brand before they had built a business that could become a brand.
They literally pissed money all over the place in sponsorship's in an effort to gain brand recognition.
They also attempted to work on wafer thin profit margins. £400 profit per vehicle was their objective. The problem they had, is that with like a lot of things purchased on line, was the level of returns. It was sky high. So the cost of picking up the rejected vehicles and returning them, simply killed any level of profitability, they were making.
The guaranteed 7 day returns period is the problem. If you buy a car from a dealer and the you think the seats are bit uncomfy or whatever, you just crack on, knowing you will eventually get used to it. With this business model, after 2 or 3 days, you just email them and tell them to come and pick it up, and that's what happened. The IPO was also a sham, totally front end loaded, so the initial investors make a killing, and the future shareholders take the loss.