If you receive your item and it is damaged, defective, or materially different, you must contact the third-party seller within fourteen (14) days of receipt to request return information. For third-party seller orders made on the Amazon.com website for eligible services, you must wait until your scheduled delivery time has elapsed to file an A-to-Z claim. Note: If your item becomes defective more than 30 days past the shipment date and it is under warranty, you must contact the manufacturer for repair or replacement. a to z 似乎已经失效了,至少amazon的policy这么写的