I submited the following as a support request:
Torchlight II was on offer during the entire Autumn sale, at 25% off. I bought it. But, on the last day of the sale, it was discounted further, to 50% off. I've not played the game yet - your records will show this.
If you really care about the gamers who use your service, then please refund the difference. It's the only decent thing to do. It was very misleading to include Torchlight II in the sale at 25% off, when you knew it would be reduced further at a specific time, within the same promotion. You were baiting users to buy the game at just 25% off, and you probably made some money out of this deception.
If you cannot do this, then cancel and refund my order - today - as is privileged to me by the UK Sale of Goods Act. Obviously, if you cannot do this today, then do not cancel my order.
The response was:
A staff member has replied to your question:
Thank you for contacting Steam Support.
Steam does not offer price matching.
For information on current sales and promotions please refer to the Steam Storefront or Steam News.
Am I being unreasonable? Did anyone else buy Torchlight II during the -25% promotion, and feel cheated?
I think the worst part is that the cold response email includes automated fluff about "getting Steam news". It's the last thing I care about, especially after carefully splashing-out on several games that I want to play - but now can't enjoy because I feel a little bitter about the whole experience.