eh, they do not have to give you the car. It isn't "yours" until you pay for it AND drive it off their property...up until then both you and the dealer can walk away.

Is it despicable? Sure.

Tell the sales rep she lied to you trying to cover up what the manager did. You will no longer deal with her- she is not to speak to you or handle any aspect of the transaction. (They all lie, but I'd do this to establish power.)

Then see what else you can get.

How good is the deal? $500 over cost? then you cannot do much. $2000 over? yes, they need to make good.