So I came across GOG due to news about the Interplay deal, and ordered - I thought - six games. However, due to problems with the shopping cart I discovered I'd also paid full price for Arx Fatalis as a seventh game. I e-mailed support to explain that I has not wanted to order Arx Fatalis, and requested a refund, and received the following response from Peter on the support team:
"Unfortunately a refund won't be possible in this case. :( Still, considering the amount of games you got for free in this order, I think it's a fair deal (plus from what I know Arx is a very unique and interesting game). ;)"
Okay, no refunds, it's $6, I'm not heartbroken. But the snark about a 'fair deal' is a bit over the line. A FAIR deal is actually following through on the promotion you advertised, and delivering what the customer wanted to pay for. Not acting like the customer is fortunate to have to pay extra for something they didn't want because your shopping cart is buggy. I expect I'll get $6 out of Arx Fatalis, as well as the other games I bought this weekend. But in the future I'll be spending my money elsewhere.

no offense, but why didn't you just check your shopping-cart before actually paying for your order?

Could you explain exactly what problem you had with the shopping cart?

Are you 100% certain that Arx wasn't in your shopping cart when you placed your order? I just find it strange that it would magically added to your cart when purchasing from the Interplay deal page, seeing that it isn't even a part of that deal. Is there any chance at all that you added it to your cart earlier from the product page and then forgot to remove it from your cart?
Either way, it's a shame that the game could not be removed from your account and a refund given. Perhaps you'll be interested in trying GOG again in the future when it is no longer in beta?

I agree.
As far as I know, GOG has never issued refunds before. Maybe you can try asking for a free game to go along with Arx?
-edit-
Nvm I just realised Arx isn't an Interplay game

Indeed. To be honest, this sounds not like a GOG error, but a PEBKAC one.

If memory serves, it gives you a list of the things you're purchasing and a total price before the payment confirmation stage so you can make sure you're buying the right things.
The GOG staff tend to be a fair bit less formal than the usual customer service reps which has both positive and negative aspects. It sounds like Peter was trying to put a positive spin on something he can't change so you didn't walk away angry. It's probably not the perfect response but it's better than a form letter saying "Dear USER. This purchase was made according to the terms of the promotion and the problem is user error. There are no refunds. Bye"

It does sound like Arx was in the cart previously. Can be done by clicking around multiple tabs and hitting the cart or purchase buttons, depending in the order it's done, tiles show up differently but the final checkout screen is what you get.
Regardless of the service, double check the order before hitting the pay/process button.

My experience from dealing with the GoG support team was nothing short of wonderful, reading your comment I was really surprised you had any issues with them
One of the issues when running a DRM free download service is the lack of ability to give refunds (for the obvious reason...)
I'm guessing Peter only tried to cheer you up , and in no way should be interpreted as "Snarky"
Saying "7 games for ~24$ is still great value"
And correct if i'm wrong Arx Fatalis was never part of the promo , so how did it get into your cart at the 1st place?
Also its kinda hard to miss any additional or missing games when you reach the check out screen considering there all listed individually ,you see the discount and the over all price
before you confirm payment , just be more careful in the future mate.
You really shouldn't let one miss interpetation give you the wrong impression

Aye. One thing you might not have realized is that your shopping cart is linked to your account, not your computer.
Amazon, for example, stores the details of your shopping cart on your computer (I think). So if you log-in from two systems, you can have two carts going.
GoG keeps your cart on your account. So if you log-in from two systems, you have the same shopping cart for both.
What likely happened was you added Arx to your account some time ago or while you were on a laptop, and then you did the Interplay deal and had forgotten about that.
That being said: Arx IS awesome :p

The no refund is because the games are 100% DRM free - if they offered refunds for 'accidents' then people could abuse the system.
As to the problem - Arx Fatalis couldn't magically be added to your cart, it had to have been there before hand. You also are given the chance to review the cart when you check out, user error for not noticing the extra game there.
As for the GoG email response.. well, they are right. You got a heck of a deal with the promo.

Let me get this straight... You added a game to your cart, then proceeded to checkout (that's two pages where you saw the game was there), purchased five games for a few pennies and asked for a refund claiming it's a bug other than your own? :) Then you got a fair but informal response and you're... What? Disappointed? Insulted? I don't get this at all... Enjoy your games, why don't you?

I'm going to have to agree with the other posters here; from the way you have described the circumstances, it seems to be your error and as such GOG is under no obligation whatsoever to correct your mistake with a refund. In fact the 'Terms of Use' you agreed to when signing up to this site also make perfectly clear that GOG will not provide refunds as a rule and that "all sales are final".
It is your own responsibility to be thorough and considered enough not buy something you don't want, nobody else's. I suggest you put it down to experience and move on.
As for the Customer Service reply, that is a different matter. Personally, I don't see too much wrong with it although it may be a little too informal for this kind of eventuality and I can see why it might irk you. If you have a problem with how you have been corresponded with, I suggest you reply, stating your concerns or contact somebody else at GOG.

LOL guy of the day.

Also are there actually sites or online services that offer refunds if you buy a game accidentally?