Sen. Amy Klobuchar, D-Minn., wrote the FCC Friday urging more attention to what she described as confusing cell phone bills and "poorly" outlined terms of service in mobile phone contracts.

She praised the FCC for its recent call for public comment on ways to alert customers before they run up high cell phone charges. "This so-called 'bill shock' concern is just one aspect of the broader problem of confusing billing practices and poorly outlined terms in cell phone contracts," Klobuchar said in a letter to FCC Chairman Julius Genachowski.

She also voiced concern again about mobile phone providers charging "outrageous early termination fees" to customers who cancel their contracts early. Klobuchar, who sits on the Senate Commerce Committee, has introduced legislation that would put limits on such fees. The FCC has requested information from wireless providers on the fees.

"I remain concerned that ETFs, at any price, are designed to prevent choice, limit competition and unfairly tie consumers to unsatisfactory contracts, and I urge you to carefully examine the contracts for each company," she said.