7 reasons your credit card gets blocked Plus: 7 tips for handling it when it happens to you When your credit card company stops a thief from charging fraudulent expenses to your card, you’re thrilled. But what happens when they mistake you for the thief? 7 reasons your credit card gets blockedWith $6.89 billion in fraud losses in 2009, credit card companies eager to stem the tide are continually beefing up their anti-fraud measures, relying on sophisticated computer software to flag suspicious transactions. Trouble is, what looks like a red flag to a computer may just be you you red-faced and frustrated. So what looks bad to your card company? Anything out of the ordinary. "The credit card companies -- Visa, MasterCard, American Express, Discover -- all have their own proprietary technologies that look for anomalies in your spending habits," says Robert Siciliano, a McAfee consultant and identity theft expert based in Boston. Siciliano suggests t...