Unfortunately, I was advised that I'm covered under a warranty tier that was incorrect

Unfortunately, I was advised that I'm covered under a warranty tier that was incorrect. I'm now stuck with a car that has the most limited warranty while I was under the impression that I was being given an unlimited package and unfortunately I had to learn this after a breakdown and now I have to cover majority of the cost. An M5 F10 DCT from the Dome, so you can imagine the difference between my expectations and reality.