Sen. Richard Blumenthal is calling for a federal probe into “deceptive marketing practices” by TurboTax.

Blumenthal says the tax filing software has been charging taxpayers after promising free services.

"That is outrageous, and we are demanding an investigation from the Federal Trade Commission of these deceptive and misleading promises free service from TurboTax,” Blumenthal said. “I'm hearing from taxpayers that they were charged hundreds of dollars and I think they deserve money back after these deceptive and misleading promises."

He says past enforcement by the FTC has proven these practices to be illegal and he’s demanding stronger action now.

The tax service provider has denied wrongdoing.