I'm not saying it is your fault. but you failed to deliver. to the buyer all he got was an excuse. you know what they say about excuses.
Suppose you ordered something from Amazon, it didn't show up but they had a good excuse. Would you want your money back?
Well in this case, you are amazon.
I've been selling a long time and I always reaize that until the package is safely delivered, it is my responsibility.
I also use Auctane shipstation through paypal to create labels. It verifies all addresses and it would have caught this. Something to condier for next time.
Jerry