Help! My Pricey Travel Credit Card Wouldn’t Work When I Traveled

I’m not going to start feeling sorry for credit card issuers any time soon, given their profits, but they do have a tricky task to perform, determining within milliseconds whether any one of a billion-plus transactions a day should be disallowed, especially considering the near-total protection they offer consumers against fraudulent use of their cards. Complicating matters further for American issuers, our credit cards can generally be used without four-digit PINs, unlike cards in many countries. The Belgian researchers could not say for sure, but they told me it was reasonable to assume that, all other things being equal, a transaction with a PIN code would be less likely to be flagged for fraud than one without.

“We look at a multitude of factors when making a decision to block a transaction for potential fraud,” Mr. Lussier, the Chase spokesman, told me. And here’s the kicker: “There are no concrete tips for consumers to use that would help them guarantee every single credit card transaction they make isn’t denied for potential fraud.”

But there are a few things you can still do, said Mr. Ewen, of The Points Guy: First, be sure your phone can receive texts and make calls from abroad, so you can both be alerted to potential fraud and call from wherever you are as soon as your card is declined. (Grace, I know you do receive text messages abroad and did not receive any from Chase, but Mr. Lussier told me that chip-reading issues would not trigger such a text.) Also, travel with multiple cards. I’d add you might even want to bring three, if you have them — two to carry, and one, perhaps an A.T.M./debit card, to leave in the hotel for emergencies. Insist on inserting cards into machines rather than tapping from the beginning of your trip, something that might (or might not!) have saved me from landing on the fraud detection radar.

Unfortunately, Grace, it looks like this time I couldn’t be of much help, and I would certainly understand if you wanted to cancel your Chase card. One consolation, though: If you do cancel, you won’t lose your points — or, at least, not their full value. For 30 days after you close your account, you can redeem them for cash; transfer them to one of Chase’s airline or hotel partners, including United, Southwest, Marriott Bonvoy and Hyatt; or even buy a new iPhone.

If you need advice about a best-laid travel plan that went awry, send an email to travel@nytimes.com.

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