We had a glitch a long time ago but it was never escalated into a charge-back. Today we got a notice that we had a disputed charge and that the buyer said it was unauthorized use of their credit card.
Now we will see how the PayPal systems works in reality since they had the sales "seller Protection-Eligible". I am handling it calmly at the moment because I think the evidence is in our favor and SOMEONE other than us will have to eat the charge, but....time will tell.
We have delivery confirmation and the buyer never said that it did not arrive, so apparently the address was correct. The buyer also left us good feedback and we have never heard of a thief worrying about leaving feedback, good or bad.
I think the misunderstanding is an internal matter within their household and that should not be our problem, but we offered to take the items back with a full refund of their purchase price. (not shipping)
We will add to this post as things develop.