I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear that this happened.
The sale of a car is final when it's made, and there unfortunately is no legal right to return the vehicle unless the contract provides for one. I've never seen one that says you can cancel if you change your mind, but you should read the contract just in case. Many dealerships will, as a customer courtesy, work with a customer who changes their mind to cancel sales and put the customer into a different, cheaper vehicle. However, this is up to the individual business, and places that do so make the choice because they rely on word of mouth referrals and repeat business. Read through your contract very carefully.
Since the car now legally belongs to you, if you were to leave it at the dealer's and refuse to remove it, they could have it towed to your house. The dealership is private property, so if the manager is telling you that you're not welcome there, it could be considered trespassing to enter. A person who is trespassing can be removed by police if necessary. The manager's behavior is completely unprofessional, and you're absolutely welcome to tell your friends how the dealership treated you before they go car shopping. But I'm afraid it's not illegal unless they threatened you with physical violence.
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