What if you think the charge on your credit card bill was a retailer's mistake -- not account fraud or theft?

The action you take is pretty much your call. You can try to straighten it out with the merchant. You can deal only with the credit card issuer. You can do a combination of both.

What you need to know: The law gives you 60 days from when you discover the billing error to notify your card issuer in writing of the error, says Lauren Bowne, staff attorney for Consumers Union.

Billing errors include such issues as a merchant double billing you or charging the wrong amount for a purchase.

That gives you some time, if you feel it might be easier to fix the problem through the merchant. "It makes sense to contact the merchant first to see if they'll fix the error," says Laureen France, investigator with the Federal Trade Commission. "And often they will."

If you're a good customer, "the merchant wants to keep you happy," says Dvorkin.

However, you're not required to talk to the retailer, Bowne says. If the merchant doesn't resolve your problem quickly -- issuing a permanent credit, not just promises -- contact your card issuer so you preserve your dispute rights. (Remember that 60-day clock.)