Federal Communications Commissioner Mignon Clyburn is not very happy with Verizon Wireless, and has gone ahead to slam the telecommunications services provider even more over its new $350 Early Termination Fees, after rejecting the explanation offered as "unsatisfying".

The firm's answers "were unsatisfying and, in some cases, troubling", Commissioner Clyburn said On Wednesday, while adding that some responses even managed to "alarm" her.

On Friday, Verizon had replied to an FCC inquiry letter, demanding explanation over the sudden hike in ETFs from $175 to $350 for users of numerous smartphones like the BlackBerry and Palm Centro. The company argued that the huge fees was imposed to subsidize the cost of the newer, more expensive mobile devices, in addition to higher advertising and expenses of customer support attached with them.

Ms. Clyburn is, however, not happy with the responses and considers this reasoning illogical.

"I am concerned about what appears to be a shifting and tenuous rationale for ETFs. No longer is the claim that ETFs are tied solely to the true cost of the wireless device; rather, they are now also used foot the bill for 'advertising costs, commissions for sales personnel, and store costs'", she asserted.

The Commissioner has now said that she and her colleagues are now all set to explore the issue over the next year.