A lot of folks post up frustrations with refunds...earlier this week, Fotolibra added a blog post about being vigilant against this type of fraud.  Essentially, the explain what happens...

http://blog.fotolibra.com/?p=2644

I have had this happen to my own credit card - the number was stolen and then "tested".  The first time it happened it was at Zoosk and the second time it happened it was at Auto Trader.

Thought those that complain about refunds might find the post of interest.