Why Amazon? A good question since many eBay sellers also sell on Amazon would you not get the same problems? The answer oddly is no. Amazon actually enforce a far stricter and fairer set of rules and actually listen and work through problems with both sellers and buyers instead of a load of canned pre-scripted replies. Amazons customer service is far, far beyond what it is on eBay. I have had refunds before instantly credited as gift cards and another/replacement item sent out all on Amazons tab. Its not hard to find tales of excellent service from Amazon reps. eBay is slowly trying to be Amazon just take a look at the listings and you will see it.
EDIT 24/12/12: Not even a day later stumble across this Amazon Representative Creates Holiday Discount in Response to Reddit Comment see they do actually listen and follow through with promises.