Not happy

We tried to buy a Car from riverhorse Valley branch and after getting pre approval from the bank and planning to go in to the branch the afternoon to sign papers then two hours later they call back and say that someone walked in and put a holding deposit on the car. Why have a potential buyer then treat someone that walks in with a holding deposit take priority. According to the T&C if someone puts down a holding deposit it stands for 24 hours for catagory B and 48 hours for Catagory A this is longer than 48 hours and the sales person says the holding deposit still stands.