“I was charged an over-limit fee when the interest charge kicked my account over my limit,” said Cressman. When he called his credit card issuer to complain, they refunded the charge. “I was told that in the future I would ‘just have to watch my balance,’” he recalled.

Over-the-limit fees aren’t the only tactic in the credit card companies’ bag of tricks. There are a slew of penalties, fees and other billing practices that can cause consumers to find themselves drowning in debt.
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But even borrowers who pay their bills on time can fall victim to deceptive practices used by the card issuers and get slammed with rising interest and hidden fees, which have become the industry norm in recent years.
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many banks calculate finance charges using what’s called double-cycle billing, a confusing practice that averages out the balance from your previous two bills. So if you carry a balance and pay a finance charge one month, you’ll get hit with a finance charge on your next bill as well, even if you’ve paid off the balance.

Then, there’s a practice known as “trailing interest” - another “gotcha” to watch out for, Arnold said. If you send in a payment according to the full amount on your statement, you may find that you still owe a small balance next month. That’s because you accrued interest between the time you sent the payment and when it was posted to your account.