So lemon laws vary by states, but they are usually pretty similar. It's usually something like the dealer gets two chances to fix it and then on the last chance if they can't fix it in x amount of days, they have to buy the car back. You basically "invoke" the law. You need to look it up for your state. I had an issue with my Camaro when my plugs had gotten fouled (which is what the end result was). For a while they jerked me around, saying it was because I let the car sit for 3 years (I had only owned it for one year at that time), or that I had been using "not top tier gas" I said I could show them the receipts from costco. They threw some other crazy stuff in there about the fuel that made no sense, like it went bad in a week. Like if you really don't know why something is wrong, fine, let's see if we can get it fixed, but don't make up obviously made-up shit and don't blame me for ridiculous things that aren't true. So I sent them a letter, one certified mail, one regular mail. That means someone has to sign for the certified letter and even if they refuse, if the regular letter doesn't come back, you can presume they were served. After a certain point, you have to cut off all phone conversations, because they aren't recorded and documented. They can deny you ever talked to them, but they can't deny they got a letter in the above conditions. I had my various items of proof where I addressed all of their claims and at the end said, you get one last chance to fix it, or I'm invoking the rule, based on the information provided. My car was detailed and waiting 3 days later. I'm not a lawyer, but in my job I work with them and build cases. IME, everyone should learn how to make official correspondence in college, because situations like this have happened more than once now, including to family members that I've helped out.
The overall take-away that I've learned in life is that when you know you are in the right and the other business party is jerking you around, it's time to stop calling and asking them to do the right thing, it's time to start sending letters. Any competent lawyer will usually tell the business to take care of it, rather than get creamed in court. A lot of the situations where this applies could be handled in small claims court, like the time the windshield installer put a big scratch in the middle of my BMW's $1500 cluster. They weren't in any big hurry to help me out...till I started sending them correspondence.