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It would be a grievance in civil law, not a crime, if the seller refunds you. But unless there is some freakish sort of consequential loss (heart attack when the expected pacemaker battery failed to appear?), it is unlikely to be worth suing over.
It is only a criminal offence if the seller tries to keep the item and also does not refund your payment.
I think it is worth reporting even the refunding seller, and saying in feedback what she did. You should do this by opening a case in the Resolution Centre on the Ebay website.
I am sure they will come down hard on her, on the basis that she should have put a reserve price on the auction.
I hope this assists and answers your question.
The seller has sold the item to a third party and not refunded