You're simply being scammed - send the money back - then sell your items local for "CASH".
This is a classic scam an they even tossed in an optional fake threat.
In order to qualify for Seller Protection, the items you sell need to be something you can ship, track and insure if applicable. Rims and tires are not something you mail so they would need to picked up in person or delivered by a 3rd party - a deal such as this would not qualify for Seller Protection.
Next, as the seller, if you had an item that could be shipped and tracked, you would send an invoice to the buyer, the buyer pays, the money is deposited into your PayPal Account Balance, once you have the money, you purchase and print a shipping label and annotate the tracking number in the the transaction record, once done - you ship the item.
As the seller, you're in charge - not the buyer.
