A leaked customer database shows how much Lizard Squad, the group that infamously brought down the Xbox and PlayStation gaming networks over Christmas, charges to launch a distributed-denial-of-service (DDoS) attack. It also shows that the hackers have quite a few dissatisfied customers out there.

The group charges between $6 and $500 in bitcoin cryptocurrency to orchestrate DDoS attacks, according to the document, the existence of which was revealed by cybersecurity journalist Brian Krebs. DDoS attacks temporarily knock websites offline by overwhelming them with Web traffic.

Krebs reported that Lizard Squad left its customer information unprotected in a plain text file, exposing not only how much each client paid for a DDoS attack but also the personal details of 13,000 “customers.” New evidence obtained by Forbes Tuesday revealed that, of those 13,000, only 250 or so actually paid for a DDoS attack, with decidedly mixed results.

“By the way, this s--- does not work, worthless,” one customer wrote. “Complete rip-off. Would like refund.”

This comes after police in the United Kingdom announced they arrested an 18-year-old in connection with the Xbox and PlayStation hacks. The individual was formally accused of unauthorized access to computer material and knowingly providing false information to U.S. law enforcement agencies.

He also was accused of “swatting” -- providing a false tip about a hostage-taking or other situation that could lead to the arrival of a SWAT team at the door of an unsuspecting person.

“We are still at the early stages of the investigation and there is still much work to be done,” Craig Jones, a member of the U.K.’s National Cyber Crime Unit, told the BBC. “We will continue to work closely with the FBI to identify those who commit offenses and hold them to account.”