[jsh1120]

I'd have to agree that the chances are MUCH greater that the source of your problem lies with your device(s) than with Amazon's servers. I'll assume you're correct that the card you use for Amazon is not used for any other purpose. Do you carry it with you? If so, it's possible that your card info may have been compromised even if the card was not stolen. And rather than signing your card, enter "SEE ID" on the back. It's not a foolproof method but it does discourage use of a stolen card.

Or do you use a public wifi network when ordering from Amazon (e.g. McDonald's, Starbuck's, etc.) If so, it's far more likely that your credit card information was lifted while you were using the card online than that Amazon's own security has been breached. I make it a practice NEVER to use any device on a public network if I have to enter a credit card number. It's risky enough to enter login and password information on a public wifi network but entering a credit card number in McDonald's is equivalent to announcing it in a loud voice.

You can, of course, use a gift card to purchase from Amazon. But as I recall, you cannot attach a gift card in place of credit card on your Amazon Account. And without a credit card, you cannot download digital content (even free content) to your Kindle Fire. An alternative is to purchase a prepaid credit card (My local grocery has them) and place a limited balance on the card.