After years of consumer complaints about unauthorized charges on their credit cards by scammers and unscrupulous businesses, Visa says it plans to help.

The company said it is aware of the growing number of abusive "negative option" marketing practices that "sell" consumers products without their consent and that it plans to better publicize the way consumers can fight back.

"Most e-commerce merchants care about their customers and conduct business fairly, but even a few bad actors can cause consumer distrust," said William M. Sheedy, Group President, The Americas, Visa Inc. "We want to let consumers know more about the protections they have against these types of practices and how to pursue a reversal of charges if they've been charged improperly."

Visa's response follows a letter from Sen. Jay Rockefeller (D-WV) asking credit card processors to do a better job of protecting consumers from the negative option, especially when it involves a "free trial." Unauthorized charges topped's annual "Top 10 Scams of 2009."

With free trials with a negative option feature, a company takes a consumer's failure to cancel as permission to begin charging. While many merchants use this billing process appropriately, others pre-check consent boxes, bury the details of the offers in the terms and conditions and make cancellations or returns difficult, catching consumers in a cycle of recurring charges for products and services they do not want.

According to a Visa survey, 29 percent of American consumers have fallen victim to deceptive marketing when unscrupulous e-commerce merchants require them to cancel or opt-out of a recurring charge for future products or services.

Visa said it monitors its payment network to identify merchants with excessive levels of cardholder disputes, which may indicate the use of deceptive marketing practices. In fact, merchants who use deceptive marketing practices have up to 20 times as many consumer disputes as the average e-commerce merchant, according to Visa's figures. Visa requires the merchant and its bank to take corrective action to reduce excessive consumer disputes, or risk termination of Visa acceptance privileges. regularly receives thousands of complaints about unauthorized charges. These charges can be for a product, such as a "trial-size" bottle of supplements, or a services, such as a "discount club" membership.

Visa offered these tips to online shoppers on how to spot deceptive free trial offers and deceptive negative option features, and how to deal with unauthorized charges:

• Take time to read and understand all terms and conditions, so a free trial doesn't turn into a costly purchase you didn't intend to make.

• Pay particular attention to any pre-checked boxes before you submit your payment card information for an order. Failing to un-check the boxes may bind you to terms and conditions you're not interested in.

• Review card statements when you get them for any unauthorized charges, and notify the card issuer promptly of any unusual activity or unauthorized charges.

• Try to resolve the situation with the merchant. If you're unsuccessful, contact the card issuer immediately to dispute the charge.

What kind of negative option marketing is acceptable? According to the FTC, it must meet these criteria:

• Disclosing material terms in an understandable manner, without making them unnecessarily long or inconsistent;

• Making the disclosures clear and conspicuous by placing them where consumers are likely to look on Web pages, by labeling disclosures (and links to them) to indicate their importance and relevance, and by using easy-to-read fonts and colors;

• Disclosing the offer's material terms before the consumer incurs a financial obligation;

• Getting consumers' affirmative consent to the offer by, for example, having them click "I Agree" And without relying on pre-checked boxes;

• Not impeding the effective operation of promised cancellation procedures and honoring cancellation requests that comply with such procedures.

If a consumer is charged in any way, other than those listed above, the consumer should contest the charges.