tracking显示“已投递”，但好几个买家反映没收到快递？

我是碰到过3次买家开INR claim，也是显示已投递。然后我给买家发邮件：
Hello,
Beginning May 1, 2016, Amazon Customer Service advised us that they will handle all claims regarding orders marked as "delivered" by a carrier and reported "not received" by the buyer. 
For information on how to proceed, please go to (paste this URL into your browser):
https://www.amazon.com/gp/help ... 3D1-2
The direct link to contacting support is: 
https://www.amazon.com/gp/help ... t-us/
We hope Amazon resolves this quickly for you, our customer.
Regards,
Seller
第一个网址是引导买家碰到这种情况时要怎么做。比如快递有可能是家人签收的，或者被放在门口，但是他没发现。让他再去确认一下。如果还没解决，就让买家向客服反映。