nissan north America refuse to honor manufacter warranty Franklin, Tennessee

To make a long story short, I own a 2009 Nissan sentra with 52,000 miles and still under the original warranty, but Nissan is refusing to honor the warranty, initially they requested me to provide them with proof that I had gotten at least sixteen oil change receipts. I provided them with those  copies and then they said warranty still want approve the repairs until they have broken down the engine and find no smudge. The engine has been broken down and no smudge was found so now they want invoice receipts. Provided the invoice receipts now no response. I have been without a vehicle for almost a month and they want fix my vehicle or give me a loaner car. Please help me with the big name company.