Tips to help consumers with disputes on credit card charges

— -- Consumers are paying close attention to all aspects of their finances these days. Plunging investments. Falling home values. And, erroneous credit card charges. When the latter are discovered, many consumers file disputes with their card issuers.

No industry statistics are available about how often such disputes are won by consumers. But to maximize their chances, consumers should know how to navigate the maze of rules governing credit card disputes.

Under federal law, "You're entitled to an investigation (of the dispute) but not entitled to a particular result," says Chi Chi Wu, staff attorney at the National Consumer Law Center.

Mike Gaynor of Chicago says he's become an unwilling expert after spending almost 10 months and more than 100 hours fighting credit card charges.

In May, Gaynor, 44, and his wife, Kerry, 39, filed a dispute with Citibank for $130,000 — an amount that has since been revised to $46,000 — after he failed to get rugs, couches and design services purchased from an interior designer. Some of the furnishings were delivered after he filed the dispute, but Gaynor said he took Citibank's advice and refused them because their delivery was extremely late. He had already bought other furnishings.

The dispute dragged on for months before MasterCard stepped in. MasterCard decided in favor of the merchant, his bank told him in a letter, because he refused delivery of the order.

Gaynor says Citibank is working with him to locate some furnishings and is considering giving him a credit for others. But that, while helpful, won't dispel his anger.

MasterCard declined comment on the consumer's case. Generally, the card association steps in only when banks can't resolve the matter and never has "preferences in the outcome," says Chris Monteiro, a MasterCard spokesman.

Citibank spokesman Samuel Wang said the bank is "working with these customers … toward a complete resolution."

Whether the issuer decides in favor of the bank or the consumer depends on whether it's a valid claim and what type of documentation each side has, says Nessa Feddis, a vice president at the American Bankers Association, a trade group.