Nitto Motivo Radial Tire - 245/40R19 98Z XL

I purchased the Nitto Motivo 245/40/19's thru another authorized reseller. The tires came with a 60,000 mile warranty and was suppose to be an upsell from the Pirelli Nero Zero A/S per the vendor. HOGWASH ! I had the tires installed by a dealer using the newest balancing machines. I rotated the tires and aligned the tires as prescribed on Nitto's recommendation. With less than 20,000 miles (1/3 the warranty) these tires should be replaced for absolute safety. These tires are NOT on a high performance vehicle, but a Buick Lacrosse CXS daily driver. I provided all receipts, proof of maintenance, proof of mileage and more to Nitto and simply asked them to replace or provide partial replacement under warranty. They put speedbump after speedbump in the way to avoid warranty repair. They even demanded that under their warranty you have to remove the tires and ship to them for further evaluation before warranty repair. How do you do this with a daily driver ?? Tires will NOT meet the warranty and its offered significantly higher than its peer brands to stand out with Nitto knowing most cannot and will not follow their warranty demands when they see lower lifespan.