Well, in case anyone was wondering...
Contacted seller through Amazon, seller said contact Amazon.
Contacted Amazon, Amazon said contact seller.
Contacted seller again, this time by phone. Seller said they have no stock and can't replace. Contact Polk for warranty.
Called Polk. New driver coming to my door, no questions asked. Polk rep on the phone said the replacement is very easy with just a screwdriver.
Started out a bit shaky but overall fairly painless assuming the driver replacement goes smoothly. Couldn't be happier with Polk customer service.