UncleCharlie, what happened in my case was exactly what you said earlier would be unethical: the venue changed more seats to Tier A (the top ticket price) as sales increased. I don't think it's unethical, since it's effectively the same thing as raising the price of the ticket in any other dynamic pricing scenario. I also don't think it's all Goldstar's fault. But I did lose money by purchasing through Goldstar, even though the tickets appeared to be discounted, and wanted people to know that that scenario can happen.
As for the refund I asked for, since the deal was only for Tier A and there was no Tier B Goldstar pricing, I only asked for a refund between what I could have bought that ticket for (B face value) and what I did pay (the Goldstar price for A). That's not a discount, but it would've made it so that I had only paid the price that I would've paid had I purchased that seat through the theater on the day that I bought the Goldstar "deal." Goldstar declined to refund even that much, so I stopped buying through them.