Ask HN: dealing with credit card fraud while selling physical products online?

Dear HN, A contract of mine is close to launch, doing e-commerce, (partially) selling physical goods. Since I will also be supporting the codebase during the first couple of months, I'm seriously investigating the possibility of fraud, and dealing with it. We're using PayPal website payments pro. Two humble questions for a safer Internet: -What crash-curse would you recommend in proactively going against this problem? Articles, papers, or anything, really, that is not a commercial offering would be nice. -In the case of fraud, how long does it take for PayPal to detect, and cancel a given fund from our account? That is, after what time shall we safely assume, that the money will be actually ours? (shipping will be immediate -but this will affect inventory management) Specifically not asking for: paypal bashing, alternative credit card processors, adding obstacle courses to our customers. Specifically looking for: stories with data, statistical breakdown for merchandise-driven industry'