Sorry to hear about your problem. Since you have gone back 4 times for the same problem & the dealer can't fix it, you probably qualify for lemon law. Unfortunately I am well versed in this subject because of my crossfire. Your state's DMV web site should have links to the specifics of their lemon law.
You can also do a search on this site for some of my posts on lemon law.
Good luck & please keep us posted.