(CBS/AP) An Ohio man whose $3,200 credit card debt mushroomed to $10,700 with interest and fees told his story Wednesday to senators, who denounced the industry for confusing billing practices and shifting interest rates.

Executives of three major banks defended their credit card practices as responsible and responsive to consumers' needs in testimony at the hearing of the Senate Homeland Security and Governmental Affairs' investigative subcommittee. Those from Citigroup Inc. and Chase Bank USA said their companies were eliminating some practices — including the one that hit Wesley Wannemacher of Lima, Ohio, with over-limit fees on his Chase card account 47 times although he went over his credit limit only three times.

The interest charges and fees on Wannemacher's account more than tripled his debt despite his having made payments averaging $1,000 a year over six years, noted Sen. Carl Levin, D-Mich., the subcommittee's chairman.

"Unfair? Clearly, I think," Levin said. He said an investigation by the panel found that "sky-high interest charges and fees are not uncommon in the credit card industry. While the Wannemacher account happened to be at Chase, penalty interest rates and fees are also employed by Bank of America, Citigroup and other major credit card issuers."

Wannemacher used a new Chase card in 2001 and 2002 to pay for expenses mostly related to his wedding. He had $3,200 in purchases, interest charges of $4,900, 47 over-limit charges totaling $1,500, late fees of $1,100, for total charges of $10,700 as of February. He paid $6,300, leaving a $4,400 balance — which Chase agreed to waive after he contacted the subcommittee staff