But it was only after I paid for the item that I realized that I just bought a HO scale no an N scale.
Deal with your own problem first.
Contact the seller and explain your error. You could (politely) add that you almost made the same mistake again with the other listing.
It could be an error on his part, and frankly it probably is, since there would be no benefit to him to list in the wrong category and have unhappy customers.
Ask for a refund and a Mutual Cancellation. He has to initiate this. When he sends it, and after he has refunded, agree promptly and leave friendly feedback. 'thanks for helping solve my problem' for example.
If he refuses, and he is allowed to refuse, you have a problem. If he ships, you would have to return the item with Confirmation of Delivery to qualify for a refund. A waste of time and money for both of you. So start with friendly communication.
As a seller I must admit that I have a lot of listings that ended up in wrong categories, especially if I was listing a lot of items and didn't notice the Item Specifics were still set for the last item I listed. I keep running into stamps listed as dress patterns and postcards listed as books. Stuff happens.
