If the seller has no current listings, then the Advanced Search will turn up no results, and you will be unable to save the seller from there. You could try a search for recently closed listings.
Or else go to your own profile page, then edit the page address.
https://www.ebay.com/usr/djsattic2
Where your username appears, enter the seller's username instead. This should lead you to the seller's profile page, provided you have the username correctly spelled and the seller is still registered, and you should be able to save the seller using the link on the right side of the profile.
