Limit the predatory use of credit card "convenience fees" by sellers of goods & services.

In the year 2015, a credit card "convenience fee" is an antiquated concept. Paying by credit card is actually just as convenience nowadays for the seller as it is for the buyer. For example, the seller of the good or service does not need to deposit checks, or risk bounced checks. Those risks and hassles are handled by the credit card company and thus why a credit card company like Visa or Mastercard charge a processing fee as a % of the overall transaction (currently 2.5%). A "convenience fee", at a maximum, should cover the processing fee incurred by the seller (so no more than 2.5%), but nothing more. My utility company should not be allowed to charge a $4 convenience fee on a $20 dollar transaction (a 20% covenience fee). This is predatory behavior and must be stopped.