You've probably received those annoying telephone calls from people trying to sell you things—usually at dinner time. Whenever you get a call from a telemarketer, you should bear in mind the possibility of fraud. While many telemarketers are legitimate, telemarketing fraud is rampant today.

Telemarketing fraud involves deception in the sale of products or services over the telephone, whether the calls are unsolicited or not. According to the National Fraud Information Center, a non-profit antifraud group, American consumers lose an estimated $4.9 billion each year through telemarketing fraud. And the FBI estimates there are 14,000 illegal telephone sales in the United States each day.

Telemarketing fraud schemes are too numerous to list, but common ones include prize offers, advance-fee loan offers, business opportunities, credit cards, travel packages, credit repair schemes, vitamins and health products, bogus investments, charities, and recovery scams.