Uncle Sam, via the Federal Trade Commission, is taking a hard line on those companies that promise reductions in your credit card interest — if you cut them a big check first.

But you don’t need Uncle Sam’s help to figure out whether you’re the target of such a scam.

The hook goes like this. A federal judge in Washington, D.C., handed the FTC a major victory May 20, ruling that three credit card telemarketing firms must shut down operations.

The three companies — AMS, Washington-based Rapid Reduction and Texas-based PDMI — all specialized in bombarding consumers with robocalls offering to slash their credit card interest rates.

But according to the FTC, which filed a lawsuit against the three firms, the fix was in. Consumers put up anywhere from $499 to $1,590 in advance fees, while the companies told them that if they didn’t get at least $2,500 back in credit card rate reductions, they would earn 100% of their money back.

But consumers were delivered less than they were promised, the FTC charges. Instead of an all-out blitz on credit card firms to slash their rates, all the card services companies produced was information on how to pay a credit card off early.

Specifically, the FTC accuses the three companies of:

• deceptively promising consumers they could reduce their credit card interest rates.
• misleading consumers about their refund policies.
• illegally calling numbers on the National Do Not Call Registry.
• failing to honor consumers’ requests not to be called again.
• making pre-recorded telemarketing calls to consumers without their express written consent.

Credit card consumers, many of whom have seen their interest rates shoot up after late payment and over-balance penalties, are easy targets for card interest rate scammers these days. But consumers and regulators seem to be catching on, although it may be too late for some customers who were fleeced by AMS, Rapid Reduction and PDMI. In fact, the Fort Worth, Texas, office of the Better Business Bureau reports that PDMI alone has received 136 complaints from consumers this year.

To make sure you’re not the victim of a credit card fraud artist, the FBI advises taking these positive steps:

1. Don't buy from an unfamiliar company. Legitimate businesses understand that you want more information about their company and are happy to comply.
2. Always check out unfamiliar companies with your local consumer protection agency, Better Business Bureau, state Attorney General, the National Fraud Information Center or other watchdog groups.
3. Obtain a salesperson's name, business identity, telephone number, street address, mailing address and business license number before you transact business. Some con artists give out false names, telephone numbers, addresses and business license numbers. Verify the accuracy of these items.
4. You must not be asked to pay in advance for services. Pay services only after they are delivered.

For a full copy of the FBI telemarketing tips list, visit FBI.gov.

—For more ways to save, spend, invest and borrow, visit MainStreet.com.