A group of U.S. House of Representatives lawmakers launched an investigation of Ticketmaster’s “potential unfair or deceptive practices” following the Taylor Swift ticket sale debacle in November.

The lawmakers, all senior members of the House Energy and Commerce Committee, wrote a letter to the CEO of Ticketmaster’s parent company, Live Nation Entertainment, Inc., Michael Rapino.

In the letter, the committee expressed concern about the “chaotic” pre-sale of tickets for Taylor Swift’s upcoming tour. They requested that company officials meet with the committee to provide information about the ticketing process by Dec. 15 for an ongoing investigation.

The committee is requesting information including specific details on “additional fees, insider reserves, dynamic pricing, restrictions on transferability, limited ticket availability, speculative ticketing, verified fan program requirements, and scalping by bots and other scammers.”

Taylor Swift’s widely anticipated “Eras” tour opened for “Verified Fan” presale on Nov. 15, allowing those who had been qualified and selected to purchase tickets. Fans signed up almost a week in advance for a chance to access tickets to the Denver show.

Fans experienced a flurry of technical difficulties, ending up in all-day queues, experiencing hours-long paused queues and getting kicked out of the system once they entered, according to a news release.

“The recent pre-sale ticketing process for Taylor Swift’s upcoming Eras tour—in which millions of fans endured delays, lockouts, and competition with aggressive scammers, scalpers, and bots— raises concerns over the potential unfair and deceptive practices that face consumers and eventgoers,” the committee’s letter states.

U.S. Rep. Diana DeGette (D-CO) wrote the letter, and it was signed by U.S. Reps. Frank Pallone, Jr. (D-NJ), Cathy McMorris Rodgers (R-WA), Morgan Griffith (R-VA), Jan Schakowsky (D-IL) and Gus Bilirakis (R-FL) signed the letter.

This investigation is not the first of its kind. In 2019, the committee launched an investigation into allegations of unfair and deceptive practices in the live event ticketing industry that led to a committee hearing in February 2020.

At the hearing, Ticketmaster North America President Amy Howe testified that the company was “committed to business practices that promote transparency, deter deceptive practices, and provide customers with the ability to enjoy a concert, show, or game.”

DeGette cited Howe’s comments in Tuesday’s letter, saying Swift’s ticket sale debacle cast serious doubt on those commitments made by the company.