I've just had a buyer from the US which I think is suspicious.  They have bought several high priced collector cards from me which were exclusive to Australia, they have zero feedback and the paypal payment is from an unregistered account. 

I've sold for over 12 years and this is the first time my spider senses are tingling.  Some things just don't sit right with me.  I am reluctant to send it as I don't think this is a genuine buyer.  Is a mutual cancellation the best way to recoup ebay fees?