Was that "sold by / ships from Amazon" or was it from a 3rd party vendor selling on Amazon Marketplace? I'd assume the latter.
3rd party fulfilled by Amazon. Shouldn't matter. Amazon put their name on the sale, the price was the normal price - which is overpriced for a battery, Amazon charged me, and Amazon refunded the money.
Sorry, but it completely does matter. Sold by Amazon means just that; Amazon is an authorized Canon dealer. Here's what Amazon says about their marketplace:
Amazon Merchants and Marketplace sellers are independent sellers* who offer a variety of new and used merchandise. When buying from a seller, your order is fulfilled directly by the seller, who also handles all customer serviceTranslation: anyone can be a vendor on Amazon, and Amazon is merely handling the payment process, much like PayPal does. If you're looking for a genuine Canon hand strap, you can find about 100 counterfeit Versions from sellers on Amazon marketplace. Fortunately for you, like PayPal, Amazon does offer a recourse if the seller turns out to be a fraud.