If a payment is pending then the seller has not yet received it and they cannot refund it to you.

It seems that the seller has sent the item before receiving cleared payment.  I am not sure why you were able to cancel a Pending payment....this is not the first time this has cropped up on the boards in recent days.  Usually you can only cancel an Unclaimed payment.

There is no point emailing ebay/paypal....get on the phone to paypal and tell them what has happened before you blame the seller for anything and leave negative feedback.