So your next step is to formally dispute the charge by writing a letter to the bank that issued your credit card. You can get wording tips from a sample letter on the Federal Trade Commission's website. Give details and point out failures to follow the rules of shipping.

Send the letter by certified mail, and with return receipt requested, to the address that your statement gives for billing inquiries — not where you usually send your payments. The letter needs to reach the plastic provider within 60 days after it mailed you the statement that contains the charge.

Mail a copy to the unresponsive company (also by certified mail, with return receipt). For added oomph, consider sending copies to your state or local consumer protection office and state attorney general.

Under the law, the credit card issuer must acknowledge your complaint in writing within 30 days of receiving it. So call if you don't hear back by then.

During the ensuing investigation phase, you can withhold payment of the disputed amount, but you must continue payments on other charges on your account, including interest. The issuer is required to resolve the dispute within two billing cycles.

Debit cards have fewer legally required protections and immediately take money from your account. So it can be harder to get a refund for late or undelivered goods. That's a good reason for using a credit card for such purchases.

But debit card shoppers who have a problem should also make an immediate call and send a follow-up letter to the issuing bank, which usually will seek a resolution, especially for longtime and valued customers.

Also of interest: Credit card fraud in hotels. >>

Sid Kirchheimer writes about consumer and health issues.