If you find a mistake in your credit report, says Steve Haynes of Olney, Md., "be aggressive." That's how he got quick action from his mortgage lender, his credit-card issuer and the credit bureau.

The Haynes family's saga began March 5, when Steve's wife, Chris, tried to use the Citibank MasterCard they have had since 1992 and the card was declined. Steve immediately called Citibank, which told him that the credit limit had been slashed from $18,000 to $1,120 because of a negative credit report the bank had received from Experian, one of the three major credit bureaus. (The Hayneses weren't officially notified of the Citibank action until three days later.) When Steve checked the couple's Experian reports the same night (you can get your credit reports free at www.annualcreditreport.com), he discovered that the potentially negative item involved a home-equity line of credit with Chevy Chase Bank. "The report wasn't specific, but I knew the information had to be in error because the account has always been in good standing," he says.

Steve filed an online dispute with Experian and called back Citibank, whose customer representative told him the bank couldn't correct the problem until it received an updated report from Experian. To speed up the process, Steve called Chevy Chase Bank and insisted on speaking to a supervisor, who promised to notify Experian of the mistake immediately.

Following up with Experian the next day, Steve was told it could take 30 to 45 days to resolve the dispute. One day later, March 7, Chevy Chase gave Steve a copy of a letter the bank had sent to both Experian and Citibank acknowledging that there was no derogatory information on the account.

But the story doesn't end there. A week later, Steve found that Citibank had charged a $35 over-limit fee "for exceeding a limit that we weren't even aware of" and that had been imposed in error. A couple of phone calls later, he reached a Citibank manager who agreed to remove the fee on the spot.

On March 18, two weeks after the original denial, Citibank sent a letter notifying the Hayneses that their credit limit had been restored. And Experian followed up with an e-mail explaining that its records had been updated as of April 12. "Be persistent," says Steve, who put that trait to good use during his career in law enforcement. "It's in your hands to correct a mistake."