I noticed a seller has relisted the same item I have won and paid and waiting for the seller to send with a tracking number. Can a seller relist the same item after the buyer has won the listing and immediately paid for it not unless the seller has a duplicate of the item. Please advise. Thank you.

I have won an auction on stamp album from a seller in the same city as where I am. After the listing closed, I paid immediately by Afterpay for the stamp album of $45.00 and postage $8.50. But the seller refused to post me the stamp album. He asked for additional postage of $6.50. But he clearly indicated the postage was $8.50 which I had paid and no charges for combined postage. Can a seller asked for additional charges after the listing closed? If he had wanted additional charges, he should have inform me at the Q & A section but he didnt. When I mentioned I will check with Trademe, he qu...