It's totally unethical and morally wrong. While there are many honest sellers at eBay, some are out-and-out cheats and liars. Still others are not completely dishonest but are lacking in courtesy and a sense of responsibility. You seem to have had the misfortune to bid on an item offered by the second or third category.
Keep a record of all communications between you and the seller. If you have paid for the item, claim a refund. If not, submit a complaint to eBay, asking to cancel the deal. Unless you do that, this crook just might claim that you refused to buy it after you won it.
It's sad that your first experience at eBay was a bad one. But such things do happen from time to time, not only at eBay, but also in other aspects of everyday life. Just chalk it down to experience and move on.