I feel your pain.
I found an Zuiko 100/2.0 a while back and even with asking questions and seeing pics of front & rear elements ... the lens had a 'chip' in an INTERNAL element. Fortunately for me, the seller took the lens back without much hassle (but admitted he intentionally did not disclose it, because the person that he bought it from didn't dislcose it to him) and I didn't have to go the Ebay dispute route.
I always want to see front & rear glass, and get a 'funny' feeling whenever someone doesn't show both ... i.e. they're either trying to hide something, or they simply aren't aware how important the rear element is. Either way, it raises the caution flag, and prompts a request for more pics and some questions to veryify its condition.
NOTE: I bought my last lens from Adorama without seeing the rear element (Zuiko 18/3.5), but I had in writing from them that the glass was optically perfect and that I could return it 100% (less shipping) if I didn't like it. Of course, KEH doesn't show elements either, but likewise has an excellent return policy.
We've probably all had a story or two (but you learn quick). I hope this works out well for you.
BTW ... with 15 different bidders and "NO QUESTIONS" asked, likely the other bidders also keyed in on the word "SUPERB" (which drove up the price, I'm sure) ... so I'd easily suggest that the listing was DEFINITELY INTENTIONALLY MISLEADING ... with the listing image hiding the obvious defect.
Good Luck.