Our sale was concluded over the phone, although we had earlier been to see the car at the shop. We needed the car for the weekend past because of visiting family, and therefore asked if the car would be available for collection on an important weekend. We were told it was available even 2 days before that. With that, we placed a deposit for the car. Of course, the important day came and they couldn't deliver. We spent the whole of that day trying to wait for them to deliver, but gave up in the end at 5pm. We have asked to cancel since we couldn't have it for the weekend we wanted it for, and have asked for our deposit back. The dealer has refused. What do we do?