You can just replace it. My mother-in-law once bought a new car and it had constant problems. My wife finally got involved and let's just say she walked out with a brand new car and they kept the old one. I have no idea what they did in terms of paperwork, whether they just sold the old one as a used car, or what, but anything can be done if you push the right buttons.
Did you pay by credit card? If so, you can possibly have the charge reversed and that will get them to move a little faster for you.