what kind of dollar amounts are we talking (other than him being dead) maybe he changed his mind on the purchase and to not risk a negative feedback let you keep the money.
or
Other reasons people pay without accepting names;
1. they just love to give people free money
2. they forgot their passwords
3. he was in a accident and his fingers were cut off at work (can't use the computer)
4. He went camping and can't find his way out of the forest
5. His wife hit him over the head with a frying pan and he can't remember anything
6. Their computer was repo'd
7. They won the lottery and retired
8. in a comma
9. they just found out they were heir to the throne in some strange country that does not have computers
10. bitter ex uses husbands credit card to make random purchases to get back at him.
11. realised their was a TM issue "capital....net"
please add if you can think of anyother funnies