First, I would go back to where you bought it and sit down with the actual guy you bought it from, the one that was pushing the warranty on you. There’s a reason he was pushing it, and it’s usually money in his/their pocket. My first sentence would be…”well, you pushed the extended warranty on me, and now I’m going to use it”. Call the warranty company first, and come armed with information, actual information from the warranty company, about whether the warranty covers this repair. If it does, then play hardball until it does cover the repair. If it doesn’t, then insist that they either pay for the repair, or take the car back and refund your money. Then be prepared to use legal leverage if need be. It’s a lemon, it had an existing problem and they know it, and only hardball will get this done.
Ask me about what happened when The Ford dealership told my wife that they wouldn’t cover a vehicle that was burning a quart of oil every 1000 miles, with 17k miles on the clock, even with a TSB out on that very repair. Long story short, it was fixed in 2 days!