How to Deal with lost parcels Sent by using Amazon Shipping

Hi Everyone.

I am looking for some help. I have sent an item to a customer. The Customer has sent me a message saying they haven’t received the item. Upon Tracking item the it is held by DPD. I have Called DPD they are saying they are unable to locate the item and told I will need to contact amazon Regarding this. I Can Send a Replacement to the customer but how do I Claim for Lost items?

Thanks