I am convinced the Japanese vendor itsuwa-shop got confused about their Jico products. Their first response was "I checked with the supplier and they said it was correct ". I sent details gleaned from your posts plus screenshots. They wrote "Please open the return request". Nothing else!
Itsuwa-shop does have the correct part in stock. Its Jico list price is twice as much as the stylus they sent me. I will be pushing eBay to get the right stylus at the original price quoted, but don’t like my chances ...