It is critical that you report the loss or theft of your credit card to the card issuer as quickly as possible. This is true for both your personal and business-purpose credit cards.

Many companies have toll-free numbers and 24-hour service to deal with such emergencies. Credit card issuers often place instructions for reporting lost or stolen cards on your monthly statement. Follow those instructions.

It's a good idea to follow-up each phone call with a letter. Include the following information:

• your account number, 
• when you noticed your card was missing, and 
• the date you first reported the loss.

Be sure to send the letter to the address the credit card issuer designates for reporting lost or stolen cards.  Do not send it with a payment—or to the address where you send your payments—unless directed to do so.

If you report the loss before your credit cards is used, the card issuer cannot hold you responsible for any unauthorized charges. If there is unauthorized use of your card before you report it missing, the most you will owe for unauthorized charges is $50 per card.

Also, if the loss involves your credit card number, but not the card itself, you have no liability for unauthorized use.

After the loss, review your billing statements carefully. If they show any unauthorized charges, write a letter to the card issuer describing each unauthorized charge.  Again, tell the card issuer the information noted in the three bullets above. Be sure to send the letter to the address provided for billing errors.