The offense: billing and fee disputes. It's hard to live without debit cards and credit cards, but mistakes in billing can cost you and harm your credit score if you don't proactively address problems.
The defense: Closely examine the bill. Any charges you didn't make? Did your APR get changed without your approval? Don't delay disputing charges, because there may be a time limit for complaints.
Second, review your credit report and notify the credit bureaus of any outstanding disputes. The report should reflect any bills you are contesting without impacting your credit score, says Stuart Rossman, director of litigation for the National Consumer Law Center.
Third, know the law. For instance, banks can't charge ATM or debit card overdraft fees unless you opt in for the coverage, says Diane Standaert, legislative counsel for the Center for Responsible Lending. If you didn't say they could, then make sure they don't.
If none of this works, contact your state or local consumer protection agency, Grant says.