I agreed a good deal for a well - specced Volvo XC90 with a main dealer. We agreed the spec and the price by email. They took a large deposit over the phone. The next day they phoned to say that they had made a mistake and I had to either pay £1200 more or acetate a lower spec model. When I told them they had entered into a contract they said as there was no paperwork they had not, and they refunded my deposit to my card. What are my rights?