I dispatched the FBM order on May 5 & May 6 delivery status shows Deliver to buyer now today. Amazon sent me an email that they will issue a refund related to this metal tray product. What is this & reason?

The Shipping address is undeliverable. Refund reason. After 25 days, how's it Possible when it's already showing customer customer gets delivery? Why refund initiated? Give me Reason