I remember this add clearly, as i too was very interested in the second to the last gecko. IT really is SUCH a shame. She is absolutely gorgeous. All i can say is i really hope you give her a good home, and make her a wonderful display animal, make the rest of her life as comfortable as possible. What i find really messed up, is the fact when i asked he was going to sell her to me for 170 dollars. Yet here he sold all to you for 500. :/ Sounds fishy to me.
Although i'm glad i saw the signs of her having mbd, i just feel so bad that this had to happen to you. D: I would just feel so devastated, not for the money loss, but also for what the animals had to go though. I mean seriously, 22.6 gram gecko laying eggs! Thats just downright wrong. Like i said before..i just really hope you make their lives more comfortable. I know for sure they are much better off in your hands than in his.
As far as getting your money back, i really wish you luck. He doesnt deserve it, especially when now he's only to go and do the same thing to other geckos as he had done to the ones now in your possession.