Cant see you getting the bass, but there is such a thing as an NPB , which is Non Performing Buyer, and is what sellers use to report a bidder who won and doesn't pay. Plenty of those around.
Was wondering if there is an NPS, Non Performing Seller. If so, open a dispute. You may not get the bass, but seller will surely get a strike or something ?
Thing is, if he's done this before, he may already have strikes against his name. You dont have this information, sadly. So do it anyway
Something happens when you get 3 strikes.