Worth a try, but take legal advice before taking any threatened action.

Remember that this sale was made under the terms of eBay's user agreement, which you both accepted.

As I said earlier, when a buyer opens a "not as described" case eBay requires the seller to arrange and pay for the item to be returned. You accepted this in the user agreement.

You also accepted that eBay would decide all disputes, including deciding whether the item has to be returned. If you failed to arrange the return of this hot tub eBay will have decided the case in your buyer's favour, and enforced a refund without the buyer having to return 1t. So your buyer can keep it or do whatever they want with it.

So take legal advice before trying to demand its return. You may find it better to try persuasion, although this isn't always effective. Sellers often lose their money and the item because they didn't arrange for the item to be returned.