Senator Ed Markey (D-MA) told Elon Musk, “Fix your businesses. Or Congress will,” after Musk snapped at the senator’s concerns about fake verified accounts on Twitter, suggesting Markey’s real account, “sounds like a parody.’

On Friday, Markey sent a tweet immediately link to a letter he wrote to Musk criticizing the new $7.99 a month Blue with verification subscription. The letter quotes a report of the Washington Post that describes how a reporter could easily create a fake verified account posing as Markey and calls on Musk to address the issue. “Twitter needs to explain how this happened and how to prevent it from happening again,” Markey writes.

Musk’s response? “Maybe it’s because your real account sounds like a parody.” The billionaire followed up with another tweet about an hour later, saying, “And why does your pp have a mask?” referring to the senator’s profile photo on Twitter showing him wearing a face covering.

Markey wasn’t too kind to Musk’s response, warning that Congress could take action against Musk and his many companies if he doesn’t straighten things out. “One of your businesses is subject to an FTC consent decree. Vehicle safety watchdog NHTSA is investigating another for killing people. And you spend your time figuring out fights online,’ Markey writes. “Repair your businesses. Or Congress will.”

While Markey clearly doesn’t represent all of Congress, the Democrats will keep their control of the Senate after the midterm elections. Markey also sits on a number of committees that could affect Musk-owned Tesla, including the Commerce, Science and Transportation Committee, and has expressed concern several times in the past about the electric vehicle manufacturer’s fully self-driving software. .