Trouble in the Amazon

I tend to buy a lot of books from Amazon as it works out loads cheaper than buying from Waterstones or elsewhere.

Whilst buying some books yesterday I came over this little "issue". I added a book to my basket and got the "other people bought these products":

Now that definitely says "our price" on there so I bought it, and then got a "marketplace order" from a separate company Yes I probably should check but the fact that it's marketplace order isn't very clear - how about putting them in separate sections in the basket, one for each seller? Wouldn't that make it easier to see that the order goes to somewhere else? I wouldn't say that it's particularly clear especially when you have several things in your basket.

So bang goes my free postage as my Amazon order doesn't come to enough and the marketplace order has postage as well.

But hold on - how much is the book really? If I search for it I get the real price:

So I now I have to work out how to get a refund (I've already canceled the order) and the marketplace seller has an order that no one wanted because Amazon has a bug. Does the seller get charged for refunding me?

Don't even get me started with how hard it is to tell Amazon that they have a problem - they seem completely unwilling to help...

Please know that we are ready to assist you; however, we do ask that you give your seller a chance to respond and resolve this first.

I understand your interest in having us contact the seller in this case. However, Amazon.co.uk Customer Service does not have processes in place to contact individual sellers on order-related issues. If you are not able to reach a seller, or the seller does not resolve a concern, we are always willing to review this matter.

Surely a bug on their site is something that they should have an issue in solving not something that they pass off to the seller as their issue.