Banks do this too. It’s an anti-fraud measure.

The amount of fraud that happens in electronic payments is absolutely staggering. As soon as someone finds out your defenses are lower than someone else, you get spammed with people testing stolen credit card numbers.

Your account can, and will, be blacklisted promptly. If your payment processor and the banks they work with don’t stop you, the credit card company will.

This kind of thing happened at every place I’ve been at where financial institutions are involved.

The size of your company does not matter. Visa has so many customers they do not need Amazon. If Amazon fucks up, they will pull the plug if something isn’t fixed.