Sorry that the seller lied about the retail price (that's what happened, right, sorry, I am very sick and on a lot of medicine, may not be reading right!). I've seen this happen very often. When I sold a Burberry Novacheck tote, I was SHOCKED by how much others were going for... I noticed that it was because most people lied about the original retail cost. I did not lie for the same bag that was selling for twice as much (near retail).
This seems to happen all the time, not only on eBay, but also sites like Bluefly and Overstock.com. I just noticed a pair of Jimmy Choos I own on Overstock... they listed the retail price as $700 when I did not pay more than $500 for them originally.
If I were you, I'd bring this up with the seller. If you had known the ACTUAL retail price, you would not have paid so much.