Hi Mate, my old dad used to tell me to never trust an estate agent or a car salesperson. They are not your real friend. They want to use lots of mind techniques to convince you that you should sign your name on the form. They have been on courses for negotiation and how to gain your confidence. In some cases the salespersons are on commission and have targets to achieve. They even have desk layouts where their chairs are set higher than yours so they can take charge by looking down on you. They have a screen that they can turn around to show you when they want you to see it and turn it back again when the screen shows the margin they are making. In the end you will be convinced that they are doing you a favour by selling you the car. It is all about the money money at the end of the day. If they did not make a profit the business would not exist.
There are good and bad car salespersons, but their job is to sell as many cars as they can.
You have definitely been let down by a dealer and you must be so disappointed.
The dealer has been named and shamed now on this forum and hopefully future customers will be aware of their incompetence. Just these posts on our forum with the word of mouth will have affected their reputation.